Clinical Reasoning: A 30-Year-Old Woman Presenting With Rapidly Progressive Dementia and Extreme Hypoglycorrhachia.

A 30-year-old woman presented with rapidly progressive dementia 1 month after the coronavirus disease 2019 infection. Repeated CSF analysis showed extreme hypoglycorrhachia, while cultures, metagenomic next-generation sequencing, and cytopathology testing of CSF were negative. Laboratory investigations for possible etiologies revealed elevated blood ammonia and cancer antigen 125. Brain MRI demonstrated bilateral symmetric diffuse cortical lesions with mild hyperintensity on T1-weighted image and postcontrast enhancement. A more thorough history and specific examinations subsequently indicated an underlying etiology. This case provides an approach for evaluating young patients with rapidly progressive dementia, extreme hypoglycorrhachia, and diffuse CNS lesions, highlighting the importance of considering a broad differential diagnosis.

ChemR23 signaling ameliorates brain injury via inhibiting NLRP3 inflammasome-mediated neuronal pyroptosis in ischemic stroke.

BACKGROUND: Inflammatory response has been recognized as a pivotal pathophysiological process during cerebral ischemia. ChemR23 signaling is involved in the pathophysiology of various inflammatory diseases. Nevertheless, the role of ChemR23 signaling in ischemic stroke remains largely unknown. METHODS: Permanent ischemic stroke mouse model was accomplished by middle cerebral artery occlusion (MCAO). Resolvin E1 (RvE1) or chemerin-9 (C-9), the agonists of ChemR23, were administered by intracerebroventricular (i.c.v) injection before MCAO induction. Then, analysis of neurobehavioral deficits and brain sampling were done at Day 1 after MCAO. The brain samples were further analyzed by histological staining, immunofluorescence, RNA sequencing, ELISA, transmission electron microscope, and western blots. Furthermore, oxygen-glucose deprivation (OGD) was employed in SH-SY5Y to mimic MCAO in vitro, and ChemR23 signaling pathway was further studied by overexpression of ChemR23 or administration of related agonists or antagonists. Analysis of cell death and related pathway markers were performed. RESULTS: ChemR23 expression was upregulated following MCAO. Under in vitro and in vivo ischemic conditions, ChemR23 deficiency or inhibition contributed to excessive NLRP3-mediated maturation and release of IL-1ß and IL-18, as well as enhanced cleavage of GSDMD-N and neuronal pyroptosis. These influences ultimately aggravated brain injury and neuronal damage. On the other hand, ChemR23 activation by RvE1 or C-9 mitigated the above pathophysiological abnormalities in vivo and in vitro, and overexpression of ChemR23 in SH-SY5Y cells also rescued OGD-induced neuronal pyroptosis. Blockade of NLRP3 mimics the protective effects of ChemR23 activation in vitro. CONCLUSION: Our data indicated that ChemR23 modulates NLRP3 inflammasome-mediated neuronal pyroptosis in ischemic stroke. Activation of ChemR23 may serve as a promising potential target for neuroprotection in cerebral ischemia.

Meta-analysis on clinical outcomes of suprapapillary versus transpapillary stent insertion in malignant biliary obstruction.

BACKGROUND/AIMS: Endoscopic biliary stenting is an essential treatment for malignant biliary obstruction (MBO). However, the optimal location for the placement of metal stents (MS) or plastic stents (PS) during the management of MBO, whether above (suprapapillary) or across (transpapillary) the sphincter of Oddi (SO), has not been thoroughly evaluated. This meta-analysis aims to compare the clinical outcomes associated with endoscopic retrograde cholangiopancreatography (ERCP)-guided biliary stents placed above and across the SO in patients with MBO. METHODS: A comprehensive search of electronic databases was carried out to identify studies published from inception to April 2022. The clinical outcomes examined including stent patency, stent occlusion, and overall adverse events (AEs) such as cholangitis, post-ERCP pancreatitis (PEP), cholecystitis, stent migration, and bleeding. The selection of a random-effects model or fixed-effects model was based on the presence of heterogeneity. RESULTS: A total of 12 articles involving 751 patients were analyzed. The findings showed that the suprapapillary approach had longer stent patency compared to the transpapillary approach (mean difference: 38.58; 95% confidence interval 16.02-61.14, P < 0.0001). Additionally, the suprapapillary approach was associated with a lower risk of stent occlusion and overall AEs (P = 0.04, P = 0.002, respectively), particularly in the incidence of PEP (P = 0.009). The incidence of cholangitis, cholecystitis, stent migration, and bleeding were similar between the suprapapillary and transpapillary approaches. The subgroup analyses indicated that suprapillary PS had a significant decrease in the incidence of stent occlusion and longer stent patency, while suprapillary MS had a significant decrease in the incidence of overall AEs and PEP than the transpapillary approach. CONCLUSION: Compared with the transpapillary approach, the suprapapillary stent had superiority in longer stent patency, lower rates of stent occlusion and overall AEs, and notably, a lower incidence of PEP. The incidence of cholangitis, cholecystitis, stent migration, and bleeding were similar between the suprapapillary and transpapillary approaches. Further large-scale randomized controlled studies are needed to confirm our findings. REGISTRATION NO: CRD42022336435.

Core overestimation of CT perfusion in patients with cardiac insufficiency who had a stroke is mediated by impaired collaterals.

BACKGROUND: We hypothesized that left ventricular systolic dysfunction (LVSD) would lead to an ischemic core overestimation in patients with acute ischemic stroke (AIS), and impaired collateral status might partly mediate this effect. OBJECTIVE: A pixel-based analysis of CT perfusion (CTP) and follow-up CT was undertaken to investigate the optimum CTP thresholds for the ischemic core if overestimation was found. METHODS: A total of 208 consecutive patients with AIS with large vessel occlusion in the anterior circulation, who received initial CTP evaluation and successful reperfusion, were retrospectively analyzed and divided into an LVSD (left ventricular ejection fraction (LVEF) ratio <50%; n=40) and a normal cardiac function (LVEF≥50%; n=168) group. Ischemic core overestimation was considered when the CTP-derived core was larger than the final infarct volume. We investigated the relationship between cardiac function, probability for core overestimation, and collateral scores using mediation analysis. A pixel-based analysis was undertaken to define the optimum CTP thresholds for ischemic core. RESULTS: LVSD was independently associated with impaired collaterals (aOR=4.28, 95% CI 2.01 to 9.80, P<0.001) and core overestimation (aOR=2.52, 95% CI 1.07 to 5.72, P=0.030). In mediation analysis, the total effect on core overestimation is composed of the direct effect of LVSD (+17%, P=0.034) and the mediated indirect effect of collateral status (+6%, P=0.020). Collaterals explained 26% of the effect of LVSD on core overestimation. Compared with relative cerebral blood flow (rCBF) thresholds of <35%, <30%, and <20%, a rCBF <25% cut-off point had the highest correlation (r=0.91) and best agreement (mean difference 3.2±7.3 mL) with the final infarct volume to determine the CTP-derived ischemic core in patients with LVSD. CONCLUSIONS: LVSD increased the possibility of ischemic core overestimation on baseline CTP, partly due to impaired collateral status, and a stricter rCBF threshold should be considered.

Impact of high-sensitivity troponin elevation and dynamic changes on 90-day mortality in patients with acute ischemic stroke after mechanical thrombectomy: results from an observational cohort.

BACKGROUND: A study was undertaken to evaluate the impact of high-sensitivity cardiac troponin I (hs-cTnI) elevation and hs-cTnI dynamic changes on 90-day mortality in patients with acute ischemic stroke (AIS) treated with mechanical thrombectomy (MT). METHODS: Patients with AIS receiving MT were included in the study. Sixty hours after AIS onset, hs-cTnI levels were measured before and after MT to determine elevated and dynamic changes. Patients were stratified into either normal or hs-cTnI elevation groups according to the pre-MT hs-cTnI cut-off value of 0.03 ng/L. hs-cTnI dynamic changes were defined as an increase or decrease of more than 20% pre-MT and post-MT, and at least one hs-cTnI level >0.03 ng/L. Multivariate Cox regression models were used to investigate the association between hs-cTnI elevation, hs-cTnI dynamic changes, and 90-day mortality in patients with AIS after MT. RESULTS: A total of 423 patients with AIS after MT were included in our final analysis, of whom only 72 (17%) showed hs-cTnI elevation. Post-MT hs-cTnI retesting was performed in 354 patients, and 90 (25.4%) patients presented with hs-cTnI dynamic changes. 119 patients died within 90 days. After adjusting for potential confounding factors, the Cox regression model showed that patients with hs-cTnI dynamic changes, rather than hs-cTnI elevation, were associated with 90-day mortality (p<0.05). Compared with the hs-cTnI non-dynamic changes, these results showed that a statistical association was present between rising hs-cTnI dynamic changes and 90-day mortality (p>0.05). CONCLUSIONS: hs-cTnI dynamic changes, dominated by the rising pattern rather than hs-cTnI elevation, were independent factors associated with 90-day mortality in patients with AIS after MT, especially in elderly subjects.

Thrombus enhancement sign on CT angiography is associated with the first pass effect of stent retrievers.

BACKGROUND: The thrombus enhancement sign (TES) is thought to be associated with the source of the stroke and thrombus composition. We investigated whether this imaging sign along with other thrombus characteristics could be used to predict the successful first pass effect (FPE) of mechanical thrombectomy. METHODS: 246 consecutive patients with acute ischemic stroke in the anterior circulation with large vessel occlusion who underwent thrombectomy with a stent retriever and clot collection were included. Patients were divided into FPE (modified Thrombolysis in Cerebral Infarction (mTICI) grade 2c or 3)/non-FPE (mTICI 0-2b) and modified FPE (mFPE) (mTICI 2b-3)/non-mFPE (mTICI 0-2a) groups based on flow restoration after the first pass. TES presence, thrombus density, thrombus length, clot burden score, and thrombus composition were compared. The association between FPE and imaging biomarkers, along with clinical and interventional parameters, was investigated by univariate and multivariate analysis. RESULTS: FPE was achieved in 85 (34.6%) patients. TES presence was significantly lower in the FPE group (64.7% vs 80.7% in the non-FPE group, p=0.008) and mFPE group (69.1% vs 81.0% in the non-mFPE group, p=0.039). Histopathological examination revealed that TES (+) thrombi contained a higher fibrin/platelet proportion (50.9% vs 46.9% in TES (-) thrombi, p=0.029) and fewer erythrocytes (43.3% vs 47.3% in TES (-) thrombi, p=0.030). Thrombus characteristics, namely shorter thrombus length (p=0.032), higher erythrocyte proportions (p=0.026), and less fibrin/platelets (p=0.014), were confirmed in patients with FPE. In multivariable analysis, TES was the only independent predictor of FPE failure (OR 0.51, 95% CI 0.28 to 0.94; p=0.031). CONCLUSIONS: TES was independently associated with first pass angiographic failure in patients treated with a stent retriever.

Potential Factors Predicting Histopathologically Upgrade Discrepancies between Endoscopic Forceps Biopsy of the Colorectal Low-Grade Intraepithelial Neoplasia and Endoscopic Resection Specimens.

Background: It was gradually accepted that endoscopic fragment biopsy (EFB) diagnosis cannot accurately guarantee the absence of higher-grade neoplasms within the lesion of the digestive tract. There are no well-established predictors for histopathologically upgrade discrepancies between EFB diagnosing colorectal low-grade intraepithelial neoplasia (LGIN) and endoscopic resection (ER) specimens. Methods: A total of 918 colorectal LGINs was histopathologically diagnosed by EFB, including 162 cases with upgrade discrepancy and 756 concordant cases. We compared clinicopathological data of EFB and ER specimens between these two groups. Multivariate analysis was performed to identify predictors for this upgrade histopathology. Results: The predominant upgrade discrepancy of LGINs diagnosed by EFB was upgrades to high-grade dysplasia (114/918, 12.4%), followed by upgrades to intramucosal carcinoma (33/918, 3.6%), submucosal adenocarcinoma (10/918, 1.1%), and advanced adenocarcinoma (5/918, 0.5%). NSAID history (OR 4.83; 95% CI, 2.27-10.27; p < 0.001), insufficient EFB number (OR 2.99; 95% CI, 1.91-4.68; p < 0.001), maximum diameter ≥ 1.0 cm (OR 6.18; 95% CI, 1.32-28.99; p = 0.021), lobulated shape (OR 2.68; 95% CI, 1.65-4.36; p < 0.001), erythema (OR 2.42; 95% CI, 1.50-3.91; p < 0.001), erosion (OR 7.12; 95% CI, 3.91-12.94; p < 0.001), surface unevenness (OR 2.31; 95% CI, 1.33-4.01; p = 0.003), and distal location of the target adenoma (OR 3.29; 95% CI, 1.68-6.41; p < 0.001) were associated with the histologically upgrade discrepancies. Conclusion: NSAID history, insufficient EFB number, adenoma size and location, and abnormal macroscopic patterns are potential predictors for upgrade histopathology of LGINs diagnosed by EFBs. The standardization of EFB number and advanced imaging techniques could minimize the risk of neglecting the potential of this upgrade histopathology.

Ubiquitin-binding domain in ABIN1 is critical for regulating cell death and inflammation during development.

ABIN1 is a polyubiquitin-binding protein known to regulate NF-κB activation and cell death signaling. Mutations in Abin1 can cause severe immune diseases in human, such as psoriasis, systemic lupus erythematosus, and systemic sclerosis. Here, we generated mice that disrupted the ubiquitin-binding domain of ABIN1 (Abin1UBD/UBD) died during later embryogenesis owing to TNFR1-mediated cell death, similar to Abin1-/- mice. Abin1UBD/UBD cells were rendered sensitive to TNF-α-induced apoptosis and necroptosis as the inhibition of ABIN1UBD and A20 recruitment to the TNF-RSC complex leads to attenuated RIPK1 deubiquitination. Accordingly, the embryonic lethality of Abin1UBD/UBD mice was rescued via crossing with RIPK1 kinase-dead mice (Ripk1K45A/K45A) or the co-deletion of Ripk3 and one allele of Fadd, but not by the loss of Ripk3 or Mlkl alone. Unexpectedly, Abin1UBD/UBD mice with the co-deletion of Ripk3 and both Fadd alleles died at E14.5. This death was caused by spontaneous RIPK1 ubiquitination-dependent multiple inflammatory cytokines over production and could be rescued by the co-deletion of Ripk1 or Tnfr1 combined with Ifnar. Collectively, these data demonstrate the importance of the ABIN1 UBD domain, which mediates the ABIN1-A20 axis, at limiting RIPK1 activation-dependent cell death during embryonic development. Furthermore, our findings reveal a previously unappreciated ubiquitin pathway that regulates RIPK1 ubiquitination by FADD/Casp8 to suppress spontaneous IKKε/TBK1 activation.

Caspase-8 auto-cleavage regulates programmed cell death and collaborates with RIPK3/MLKL to prevent lymphopenia.

Caspase-8 is an initiator of death receptor-induced apoptosis and an inhibitor of RIPK3-MLKL-dependent necroptosis. In addition, caspase-8 has been implicated in diseases such as lymphoproliferation, immunodeficiency, and autoimmunity in humans. Although auto-cleavage is indispensable for caspase-8 activation, its physiological functions remain poorly understood. Here, we generated a caspase-8 mutant lacking E385 in auto-cleavage site knock-in mouse (Casp8ΔE385/ΔE385). Casp8ΔE385/ΔE385 cells were expectedly resistant to Fas-induced apoptosis, however, Casp8ΔE385/ΔE385 cells could switch TNF-α-induced apoptosis to necroptosis by attenuating RIPK1 cleavage. More importantly, CASP8(ΔE385) sensitized cells to RIPK3-MLKL-dependent necroptosis through promoting complex II formation and RIPK1-RIPK3 activation. Notably, Casp8ΔE385/ΔE385Ripk3-/- mice partially rescued the perinatal death of Ripk1-/- mice by blocking apoptosis and necroptosis. In contrast to the Casp8-/-Ripk3-/- and Casp8-/-Mlkl-/- mice appearing autoimmune lymphoproliferative syndrome (ALPS), both Casp8ΔE385/ΔE385Ripk3-/- and Casp8ΔE385/ΔE385Mlkl-/- mice developed transplantable lymphopenia that could be significantly reversed by RIPK1 heterozygosity, but not by RIPK1 kinase dead mutation. Collectively, these results demonstrate previously unappreciated roles for caspase-8 auto-cleavage in regulating necroptosis and maintaining lymphocytes homeostasis.

Arterial wall injury and miRNA expression induced by stent retriever thrombectomy under stenotic conditions in a dog model.

BACKGROUND: Acute ischemic stroke can be caused by in situ stenotic vessel occlusion. In the present study, we compared the extent of arterial wall damage and miRNA expression following stent retriever use under normal and stenotic conditions. METHODS: The stent retriever procedure was simulated in three dogs by the creation of four stenoses on each side of the common carotid artery (CCA) to allow five stent passages. Device safety was also assessed in normal control models by five passages through both CCAs. Device manipulation-related damage to the arterial walls was evaluated and compared between groups by angiography and pathological analysis. Real-time PCR was used to evaluate the differences in the expression of miRNAs between the two groups. RESULTS: Twenty-four stenoses were created in three model dogs, and the mean stenosis rate was 65.58%±18.95%. Angiography revealed greater vasospasm in the stenotic group than in the non-stenotic group (1.17±0.17 vs 0.5±0.23; P=0.04). Pathological examination revealed that SR passage through the stenotic lumen caused higher injury scores (1.63±0.19 vs 0.25±0.09 for the non-stenotic lumen; P<0.001), more endothelial denudation (1.79±0.13 vs 0.58±0.13 for the non-stenotic lumen; P<0.001), and increased thrombus deposition (0.71±0.14 vs 0±0 for the non-stenotic lumen; P<0.001). miR21-3p, miR29-3p, and miR26a were upregulated in stenotic vessels compared with non-stenotic vessels after SR thrombectomy (P<0.001). CONCLUSION: In our model dogs, SR thrombectomy resulted in more severe tissue damage to the arterial wall under stenotic conditions than under non-stenotic conditions. The damage may have resulted from upregulation of miR21-3p, miR29-3p, and miR26a expression.

Role of Post-Transcriptional Control of Calpain by miR-124-3p in the Development of Alzheimer's Disease.

Alzheimer's disease (AD) is a neurodegenerative disease prevalent in aged people, clinically characterized by progressive memory loss, behavioral and learning dysfunction, and cognitive deficits. The pathogenesis of AD is hallmarked by formation of amyloid-ß peptide aggregates (Aß) and intraneuronal neurofibrillary tangles (NFTs), which are induced by hyperphosphorylation of amyloid-ß protein precursor and tau protein, respectively. The hyperphosphorylation is controlled by cyclin-dependent kinase-5 (CDK5), the aberrant activation of which is mediated by calpain (CAPN)-induced cleavage of p35 into p25. However, the regulation of CAPN in AD remains largely unknown. Here, we studied the post-transcriptional control of CAPN1 by microRNAs (miRNAs) in the setting of AD. We found that miR-124-3p, previously reported as a miRNA that was downregulated in AD, was a CAPN1-targeting miRNA that functionally inhibited the protein translation of CAPN1 in a human neural cell line, HCN-2. In vitro, transfection with miR-124-3p reduced the levels of CAPN1 protein, the cleavage of p35 into p25, and cell apoptosis dose-dependently in HCN-2 cells. Moreover, a significant inverse correlation was detected between the levels of miR-124-3p and CAPN1 in AD specimens. Furthermore, intracranial injection of adeno-associated virus expressing miR-124-3p into APP/PS1-AD mice significantly reduced Aß deposition and significantly improved the AD-mouse behavior in the social recognition test and plus-maze discriminative avoidance task. Together, our data suggest that post-transcriptional control of calpain by miR-124-3p plays an essential role in the development of AD.

Aquaporin-4 deletion ameliorates hypoglycemia-induced BBB permeability by inhibiting inflammatory responses.

BACKGROUND: Severe hypoglycemia induces brain edema by upregulating aquaporin-4 (AQP4) expression and by degrading tight junctions. Acute severe hypoglycemia induces a proinflammatory environment that may contribute to a disruption in the epithelial barrier by decreasing tight junction protein expression. Interestingly, the altered AQP4 expression has been considered to play a critical role in neuroinflammation during acute brain injury. It has been shown that AQP4 deletion reduces brain inflammation in AQP4-null mice after intracerebral LPS injection. However, the effect of AQP4 deletion regarding protection against hypoglycemia-induced blood-brain barrier (BBB) breakdown is unknown. METHODS: An acute severe hypoglycemic stress model was established via injection of 4 unit/kg body weight of insulin. Evans blue (EB) staining and water measurement were used to assess BBB permeability. Western blot, reverse transcription polymerase chain reaction, and immunofluorescence were used to detect the expression of related proteins. The production of cytokines was assessed via enzyme-linked immunosorbent assay. RESULTS: Hypoglycemia-induced brain edema and BBB leakage were reduced in AQP4-/- mice. AQP4 deletion upregulated PPAR-γ and inhibited proinflammatory responses. Moreover, knockdown of aquaporin-4 by small interfering RNA in astrocytes co-cultured with endothelial cells effectively reduced transendothelial permeability and degradation of tight junctions. Treatment with PPAR-γ inhibitors showed that upregulation of PPAR-γ was responsible for the protective effect of AQP4 deletion under hypoglycemic conditions. CONCLUSIONS: Our data suggest that AQP4 deletion protects BBB integrity by reducing inflammatory responses due to the upregulation of PPAR-γ expression and attenuation of proinflammatory cytokine release. Reduction in AQP4 may be protective in acute severe hypoglycemia.

No inferiority of Tonbridge thrombectomy device for acute thrombus retrial compared with Solitaire device: an experimental evaluation with a canine distal external carotid-maxillary artery occlusion model.

INTRODUCTION: Mechanical thrombectomy (MT) has been widely accepted as a safe and effective treatment for acute ischemic stroke (AIS). Development of stent retriever devices has been intensively developed over the past two decades. In this study, we compared the effectiveness and safety of a new thrombectomy device with Solitaire FR for the treatment of AIS models. METHODS: Mechanical performance of stent retrievers was tested in vitro. Thrombin-induced thrombus was pre-injected into the right distal external carotid-maxillary artery in 18 dogs to create an acute thrombus occlusion model, and these animals were divided into a Tonbridge group (n=9, with Tonbridge stent Tonbridge Medical Technology) and a Solitaire group as control (n=9, with Solitaire stent, ev3 Neurovascular). Final flow restoration, side branches, recanalization time, distal vessel embolism, and device-related complications were recorded and compared. A post-procedure angiogram was obtained at 30 and 90 days after thrombectomy. Device manipulation-related damage to the arterial walls was evaluated histologically. RESULTS: In vitro test showed that the maximum friction within the microcatheter was 0.763 for the Tonbridge device and 0.784 n for the Solitaire (P>0.05). Slight increase in radial force was noticed for the Tonbridge (0.035 N/mm vs 0.031 N/mm of Solitaire, P>0.05). Eighteen and 16 retriever attempts were done in the Tonbridge (mean 2.0 attempts) and the Solitaire (mean 1.8 attempts) groups (P=0.74). The Tonbridge device led to good flow restoration in all nine (100%) models compared with eight (88.9%) in the Solitaire group (P=0.30). Side branches' influence (P=0.39), distal thromboembolism (P=0.60), and device-related complications (P=1.00) found no difference between the two groups. The rates of disruption of the internal elastic lamina (IEL) were 8.3% (2/24) and 4.2% (1/24) of the specimens, respectively (P=0.683). TICI 2b/3 flow of the right CCA were similar between the two groups at 1 (6/6 vs 6/6) and 3 months (6/6 vs 6/6) follow-up (P>0.05). CONCLUSION: Our preliminary study indicated this new device was technically feasible and effective to be used in thrombectomy for the treatment of acute thrombus occlusion in canine models.

Protective effects of vascular endothelial growth factor in cultured brain endothelial cells against hypoglycemia.

Hypoglycemia is a common and serious problem among patients with type 1 diabetes receiving treatment with insulin. Clinical studies have demonstrated that hypoglycemic edema is involved in the initiation of hypoglycemic brain damage. However, the mechanisms of this edema are poorly understood. Vascular endothelial growth factor (VEGF), a potent regulator of blood vessel function, has been observed an important candidate hormone induced by hypoglycemia to protect neurons by restoring plasma glucose. Whether VEGF has a protective effect against hypoglycemia-induced damage in brain endothelial cells is still unknown. To investigate the effects of hypoglycemia on cerebral microvascular endothelial cells and assess the protective effect of exogenous VEGF on endothelial cells during hypoglycemia, confluent monolayers of the brain endothelial cell line bEnd.3 were treated with normal (5.5 mM glucose), hypoglycemic (0, 0.5, 1 mM glucose) medium or hypoglycemic medium in the presence of VEGF. The results clearly showed that hypoglycemia significantly downregulated the expression of claudin-5 in bEnd.3 cells, without affecting ZO-1 and occludin expression and distribution. Besides, transendothelial permeability significantly increased under hypoglycemic conditions compared to that under control conditions. Moreover, the hypoglycemic medium in presence of VEGF decreased endothelial permeability via the inhibition of claudin-5 degradation and improved hypoglycemia-induced cell toxicity. Furthermore, Glucose transporter-1 (Glut-1) and apoptosis regulator Bcl-2 expression were significantly upregulated. Taken together, hypoglycemia can significantly increase paraendocellular permeability by downregulating claudin-5 expression. We further showed that VEGF protected brain endothelial cells against hypoglycemia by enhancing glucose passage, reducing endothelial cell death, and ameliorating paraendocellular permeability.