PI3Kγ (Phosphoinositide 3-Kinase-γ) Inhibition Attenuates Tissue-Type Plasminogen Activator-Induced Brain Hemorrhage and Improves Microvascular Patency After Embolic Stroke

Contribution of platelets to disruption of the blood-brain barrier during arterial baroreflex dysfunction

BACKGROUND

Arterial baroreflex dysfunction, like many other central nervous system disorders, involves disruption of the blood-brain barrier, but what causes such disruption in ABR dysfunction is unclear. Here we explored the potential role of platelets in this disruption.

METHODS

ABR dysfunction was induced in rats using sinoaortic denervation, and the effects on integrity of the blood-brain barrier were explored based on leakage of Evans blue or FITC-dextran, while the effects on expression of CD40L in platelets and of key proteins in microvascular endothelial cells were explored using immunohistochemistry, western blotting and enzyme-linked immunosorbent assay. Similar experiments were carried out in rat brain microvascular endothelial cell line, which we exposed to platelets taken from rats with ABR dysfunction.

RESULTS

Sinoaortic denervation permeabilized the blood-brain barrier and downregulated zonula occludens-1 and occludin in rat brain, while upregulating expression of CD40L on the surface of platelets and stimulating platelet aggregation. Similar effects of permeabilization and downregulation were observed in healthy rats that received platelets from animals with ABR dysfunction, and in rat brain microvascular endothelial cells, but only in the presence of lipopolysaccharide. These effects were associated with activation of NF-κB signaling and upregulation of matrix metalloprotease-9. These effects of platelets from animals with ABR dysfunction were partially blocked by neutralizing antibody against CD40L or the platelet inhibitor clopidogrel.

CONCLUSION

During ABR dysfunction, platelets may disrupt the blood-brain barrier when CD40L on their surface activates NF-kB signaling within cerebral microvascular endothelial cells, leading to upregulation of matrix metalloprotease-9. Our findings imply that targeting CD40L may be effective against cerebral diseases involving ABR dysfunction.

Risk Factors, Pathophysiologic Mechanisms, and Potential Treatment Strategies of Futile Recanalization after Endovascular Therapy in Acute Ischemic Stroke

Endovascular therapy is the first-line treatment for acute ischemic stroke. However, studies have shown that, even with the timely opening of occluded blood vessels, nearly half of all patients treated with endovascular therapy for acute ischemic stroke still have poor functional recovery, a phenomenon called "futile recanalization.". The pathophysiology of futile recanalization is complex and may include tissue no-reflow (microcirculation reperfusion failure despite recanalization of the occluded large artery), early arterial reocclusion (reocclusion of the recanalized artery 24-48 hours post endovascular therapy), poor collateral circulation, hemorrhagic transformation (cerebral bleeding following primary ischemic stroke), impaired cerebrovascular autoregulation, and large hypoperfusion volume. Therapeutic strategies targeting these mechanisms have been attempted in preclinical research; however, translation to the bedside remains to be explored. This review summarizes the risk factors, pathophysiological mechanisms, and targeted therapy strategies of futile recanalization, focusing on the mechanisms and targeted therapy strategies of no-reflow to deepen the understanding of this phenomenon and provide new translational research ideas and potential intervention targets for improving the efficacy of endovascular therapy for acute ischemic stroke.

USP14 inhibition promotes recovery by protecting BBB integrity and attenuating neuroinflammation in MCAO mice

AIM

Blood-brain barrier (BBB) dysfunction is one of the hallmarks of ischemic stroke. USP14 has been reported to play a detrimental role in ischemic brain injury. However, the role of USP14 in BBB dysfunction after ischemic stroke is unclear.

METHODS

In this study, we tested the role of USP14 in disrupting BBB integrity after ischemic stroke. The USP14-specific inhibitor IU1 was injected into middle cerebral artery occlusion (MCAO) mice once a day. The Evans blue (EB) assay and IgG staining were used to assess BBB leakage 3 days after MCAO. FITC-detran test was slected to examine the BBB leakage in vitro. Behavior tests were conducted to evaluate recovery from ischemic stroke.

RESULTS

Middle cerebral artery occlusion increased endothelial cell USP14 expression in the brain. Furthermore, the EB assay and IgG staining showed that USP14 inhibition through IU1 injection protected against BBB leakage after MCAO. Analysis of protein expression revealed a reduction in the inflammatory response and chemokine release after IU1 treatment. In addition, IU1 treatment was found to rescue neuronal loss resulting from ischemic stroke. Behavior tests showed a positive effect of IU1 in attenuating brain injury and improving motor function recovery. In vitro study showed that IU1 treatment could alleviate endothelial cell leakage induced by OGD in cultured bend.3 cells through modulating ZO-1 expression.

CONCLUSIONS

Our results demonstrate a role for USP14 in disrupting the integrity of the BBB and promoting neuroinflammation after MCAO.

Blocking of PI3-kinase beta protects against cerebral ischemia/reperfusion injury by reducing platelet activation and downstream microvascular thrombosis in rats

Phosphoinositide 3-kinase beta (PI3Kβ) plays an important role in platelet activation and thrombosis, but its role in stroke pathology remains unknown. In this study, we investigated whether inhibition of PI3Kβ protects against cerebral ischemia/reperfusion (I/R) injury by preventing circulating platelet activation and downstream microvascular thrombosis. We used a rat intraluminal filament model of transient middle cerebral artery occlusion (tMCAO) because the rapid restoration of cerebral blood flow to the ischemic area in both tMCAO and endovascular thrombectomy provides clinical relevance for this model. The results showed that TGX221, a selective PI3Kβ inhibitor, treatment immediately before the onset of reperfusion dose-dependently reduced infarct volume and improved neurological function. The protective effects were associated with blocking platelet activation and thrombotic response, thereby reducing downstream microvascular thrombosis, and maintaining reperfusion efficiency. These results suggest that PI3Kβ might be a promising target for treating downstream microvascular thrombosis induced by cerebral I/R injury and offer a novel adjunctive treatment to improve reperfusion therapy for acute ischemic stroke.

Mesenchymal stem cell-derived extracellular vesicles attenuate tPA-induced blood-brain barrier disruption in murine ischemic stroke models

Intracerebral hemorrhage following blood-brain barrier (BBB) disruption resulting from thrombolysis of ischemic stroke with tissue plasminogen activator (tPA) remains a critical clinical problem. Mesenchymal stem cell-derived extracellular vesicles (MSC-EVs) are promising nanotherapeutic agents that have the potential to repair the BBB after ischemic stroke; however, whether they can attenuate BBB disruption and hemorrhagic transformation after tPA thrombolysis is largely unknown. Here, we observed that MSC-EVs efficiently passed through the BBB and selectively accumulated in injured brain regions in ischemic stroke model mice in real time using aggregation-induced emission luminogens (AIEgens), which exhibit better tracking ability than the commercially available tracer DiR. Moreover, tPA administration promoted the homing of MSC-EVs to the ischemic brain and increased the uptake of MSC-EVs by astrocytes. Furthermore, the accumulated MSC-EVs attenuated the tPA-induced disruption of BBB integrity and alleviated hemorrhage by inhibiting astrocyte activation and inflammation. Mechanistically, miR-125b-5p delivered by MSC-EVs played an indispensable role in maintaining BBB integrity by targeting Toll-like receptor 4 (TLR4) and inhibiting nuclear transcription factor-kappaB (NF-κB) signaling in astrocytes. This study provides a noninvasive method for real-time tracking of MSC-EVs in the ischemic brain after tPA treatment and highlights the potential of MSC-EVs as thrombolytic adjuvants for ischemic stroke. STATEMENT OF SIGNIFICANCE: Although tPA thrombolysis is the most effective pharmaceutical strategy for acute ischemic stroke, its clinical application and therapeutic efficacy are challenged by tPA-induced BBB disruption and hemorrhagic transformation. Our study demonstrated that MSC-EVs can act as an attractive thrombolytic adjuvant to repair the BBB and improve thrombolysis in a mouse ischemic stroke model. Notably, by labeling MSC-EVs with AIEgens, we achieved accurate real-time imaging of MSC-EVs in the ischemic brain and therapeutic visualization. MSC-EVs inhibit astrocyte activation and associated inflammation through miR-125b-5p/TLR4/NF-κB pathway. Consequently, we revealed that MSC-EVs combined with tPA thrombolysis may be a promising approach for the treatment of ischemic stroke in clinical setting.

Inhibition of Phosphoinositide 3-Kinase Gamma Protects Endothelial Cells via the Akt Signaling Pathway in Sepsis-Induced Acute Kidney Injury

INTRODUCTION

Sepsis is a primary cause of death in critically ill patients and is characterized by multiple organ dysfunction, including sepsis-induced acute kidney injury (AKI), which contributes to high mortality in sepsis. However, its pathophysiological mechanisms remain unclear. The kidney has one of the richest and most diversified endothelial cell populations in the body. This study was designed to investigate the effects of endothelial dysfunction in sepsis-induced AKI and explore possible intervention measures to offer new insight into the pathogenesis and treatment of sepsis-induced AKI.

METHODS

The circulating levels of endothelial adhesion molecules were detected in patients with sepsis and healthy controls to observe the role of endothelial damage in sepsis and sepsis-induced AKI. A murine sepsis model induced by cecal ligation and perforation was pretreated with a phosphoinositide 3-kinase gamma (PI3Kγ) inhibitor (CZC24832), and survival, kidney damage, and renal endothelial injury were assessed by pathological examination, immunohistochemistry, quantitative polymerase chain reaction, and Western blotting. Lipopolysaccharides and CZC24832 were administered to human umbilical vein endothelial cells in vitro, and endothelial cell function and the expression of adhesion molecules were evaluated.

RESULTS

Endothelial damage was more serious in sepsis-induced AKI than that in non-AKI, and the inhibition of PI3Kγ alleviates renal endothelial injury in a murine sepsis model, protecting endothelial cell function and repairing endothelial cell injury through the Akt signaling pathway.

CONCLUSIONS

In this study, endothelial cell dysfunction plays an important role in sepsis-induced AKI, and the inhibition of PI3Kγ alleviates endothelial cell injury in sepsis-induced AKI through the PI3Kγ/Akt pathway, providing novel targets for treating sepsis and related kidney injury.

J147 Reduces tPA-Induced Brain Hemorrhage in Acute Experimental Stroke in Rats

Background and purpose

J147, a novel neurotrophic compound, was originally developed to treat aging-associated neurological diseases. Based on the broad spectrum of cytoprotective effects exhibited by this compound, we investigated whether J147 has cerebroprotection for acute ischemic stroke and whether it can enhance the effectiveness of thrombolytic therapy with tissue plasminogen activator (tPA).

Methods

Rats were subjected to transient occlusion of the middle cerebral artery (tMCAO) by insertion of an intraluminal suture or embolic middle cerebral artery occlusion (eMCAO), and treated intravenously with J147 alone or in combination with tPA.

Results

We found that J147 treatment significantly reduced infarct volume when administered at 2 h after stroke onset in the tMCAO model, but had no effect in eMCAO without tPA. However, combination treatment with J147 plus tPA at 4 h after stroke onset significantly reduced infarct volume and neurological deficits at 72 h after stroke compared with saline or tPA alone groups in the eMCAO model. Importantly, the combination treatment significantly reduced delayed tPA-associated brain hemorrhage and secondary microvascular thrombosis. These protective effects were associated with J147-mediated inhibition of matrix metalloproteinase-9 (MMP9), 15-lipoxygenase-1, and plasminogen activator inhibitor (PAI) expression in the ischemic hemispheres (predominantly in ischemic cerebral endothelium). Moreover, the combination treatment significantly reduced circulating platelet activation and platelet-leukocyte aggregation compared with saline or tPA alone groups at 24 h after stroke, which might also contribute to reduced microvascular thrombosis and neuroinflammation (as demonstrated by reduced neutrophil brain infiltration and microglial activation).

Conclusion

Our results demonstrate that J147 treatment alone exerts cerebral cytoprotective effects in a suture model of acute ischemic stroke, while in an embolic stroke model co-administration of J147 with tPA reduces delayed tPA-induced intracerebral hemorrhage and confers cerebroprotection. These findings suggest that J147-tPA combination therapy could be a promising approach to improving the treatment of ischemic stroke.

QiShenYiQi Inhibits Tissue Plasminogen Activator-Induced Brain Edema and Hemorrhage after Ischemic Stroke in Mice

Background: Thrombolysis with tissue plasminogen activator (tPA) remains the only approved drug therapy for acute ischemic stroke. However, delayed tPA treatment is associated with an increased risk of brain hemorrhage. In this study, we assessed whether QiShenYiQi (QSYQ), a compound Chinese medicine, can attenuate tPA-induced brain edema and hemorrhage in an experimental stroke model. Methods: Male mice were subjected to ferric chloride-induced carotid artery thrombosis followed by mechanical detachment of thrombi. Then mice were treated with QSYQ at 2.5 h followed by administration of tPA (10 mg/kg) at 4.5 h. Hemorrhage, infarct size, neurological score, cerebral blood flow, Evans blue extravasation, FITC-labeled albumin leakage, tight and adherens junction proteins expression, basement membrane proteins expression, matrix metalloproteinases (MMPs) expression, leukocyte adhesion, and leukocyte infiltration were assessed 24 h after tPA administration. Results: Compared with tPA alone treatments, the combination therapy of QSYQ and tPA significantly reduced hemorrhage, infarction, brain edema, Evans blue extravasation, albumin leakage, leukocyte adhesion, MMP-9 expression, and leukocyte infiltration at 28.5 h after stroke. The combination also significantly improved the survival rate, cerebral blood flow, tight and adherens junction proteins (occludin, claudin-5, junctional adhesion molecule-1, zonula occludens-1, VE-cadherin, α-catenin, β-catenin) expression, and basement membrane proteins (collagen IV, laminin) expression. Addition of QSYQ protected the downregulated ATP 5D and upregulated p-Src and Caveolin-1 after tPA treatment. Conclusion: Our results show that QSYQ inhibits tPA-induced brain edema and hemorrhage by protecting the blood-brain barrier integrity, which was partly attributable to restoration of energy metabolism, protection of inflammation and Src/Caveolin signaling activation. The present study supports QSYQ as an effective adjunctive therapy to increase the safety of delayed tPA thrombolysis for ischemic stroke.

Anti-inflammatory Activity of a Polypeptide Fraction From Achyranthes bidentate in Amyloid β Oligomers Induced Model of Alzheimer's Disease

Neuroinflammation plays a crucial role in neurodegenerative diseases such as Alzheimer's disease (AD) and Parkinson's disease (PD), and anti-inflammation has been considered as a potential therapeutic strategy. Achyranthes bidentate polypeptide fraction k (ABPPk) was shown to protect neurons from death and suppress microglia and astrocyte activation in PD model mice. However, how ABPPk regulates neuroinflammation to exert a neuroprotective role remains unclear. Toxic Aβ oligomers (AβOs) can trigger inflammatory response and play an important role in the pathogenesis of AD. In the present study, for the first time, we investigated the effects and underlying mechanisms of ABPPk on neuroinflammation in AβOs-induced models of AD. In vitro, ABPPk pretreatment dose-dependently inhibited AβOs-induced pro-inflammatory cytokines mRNA levels in BV2 and primary microglia. ABPPk pretreatment also reduced the neurotoxicity of BV2 microglia-conditioned media on primary hippocampal neurons. Furthermore, ABPPk down-regulated the AβOs-induced phosphorylation of IκBα and NF-κB p65 as well as the expression of NLRP3 in BV2 microglia. In vivo, ABPPk pre-administration significantly improved locomotor activity, alleviated memory deficits, and rescued neuronal degeneration and loss in the hippocampus of AβOs-injected mice. ABPPk inhibited the activation of microglia in hippocampal CA3 region and suppressed the activation of NF-κB as well as the expression of NLRP3, cleaved caspase-1, and ASC in the brain after AβOs injection. ABPPk hindered the release of pro-inflammatory cytokines and promoted the release of anti-inflammatory cytokines in the brain. Notably, the polarization experiment on BV2 microglia demonstrated that ABPPk inhibited M1-phenotype polarization and promoted M2-phenotype polarization by activating the LPS- or AβOs-impaired autophagy in microglia. Taken together, our observations indicate that ABPPk can restore the autophagy of microglia damaged by AβOs, thereby promoting M2-phenotype polarization and inhibiting M1-phenotype polarization, thus playing a role in regulating neuroinflammation and alleviating neurotoxicity.

Influence of prior intravenous thrombolysis on outcome after failed mechanical thrombectomy: ETIS registry analysis

BACKGROUND

Despite constant improvements in recent years, sufficient reperfusion after mechanical thrombectomy (MT) is not reached in up to 15% of patients with large vessel occlusion stroke (LVOS). The outcome of patients with unsuccessful reperfusion after MT especially after intravenous thrombolysis (IVT) use is not known. We investigated the influence of initial IVT in this particular group of patients with failed intracranial recanalization.

METHODS

We conducted a retrospective analysis of the Endovascular Treatment in Ischemic Stroke (ETIS) registry from January 2015 to December 2019. Patients presenting with LVOS of the anterior circulation and final modified Thrombolysis in Cerebral Infarction score (mTICI) of 0, 1 or 2a were included. Posterior circulation, isolated cervical carotid occlusions and successful reperfusions (mTICI 2b, 2c or 3) were excluded. The primary endpoint was favorable outcome (modified Rankin Scale score of 0-2) after 3 months. Secondary endpoints were safety outcomes including mortality, any intracranial hemorrhage (ICH), parenchymal hematoma (PH) and symptomatic intracranial hemorrhage (sICH) rates.

RESULTS

Among 5076 patients with LVOS treated with MT, 524 patients with insufficient recanalization met inclusion criteria, of which 242 received IVT and 282 did not. Functional outcome was improved in the MT+IVT group compared with the MT alone group, although the difference did not reach statistical significance (23.0% vs 12.9%; adjusted OR=1.82; 95% CI 0.98 to 3.38; p=0.058). However, 3 month mRS shift analysis showed a significant benefit of IVT (adjusted OR=1.68; 95% CI 1.56 to 6.54). ICH and sICH rates were similar in both groups, although PH rate was higher in the MT+IVT group (adjusted OR=3.20; 95% CI 1.56 to 6.54).

CONCLUSIONS

Among patients with LVOS in the anterior circulation and unsuccessful MT, IVT was associated with improved functional outcome even after unsuccessful MT. Despite recent trials questioning the place of IVT in the LVOS reperfusion strategy, these findings emphasize a subgroup of patients still benefiting from IVT.

The Protective Role of Immunomodulators on Tissue-Type Plasminogen Activator-Induced Hemorrhagic Transformation in Experimental Stroke: A Systematic Review and Meta-Analysis

Background: Recanalization with tissue plasminogen activator (tPA) is the only approved agent available for acute ischemic stroke. But delayed treatment of tPA may lead to lethal intracerebral hemorrhagic transformation (HT). Numerous studies have reported that immunomodulators have good efficacy on tPA-induced HT in ischemic stroke models. The benefits of immunomodulators on tPA-associated HT are not clearly defined. Here, we sought to conduct a systematic review and meta-analysis of preclinical studies to further evaluate the efficacy of immunomodulators.

Methods: The PubMed, Web of Science, and Scopus electronic databases were searched for studies. Studies that reported the efficacy of immunomodulators on tPA-induced HT in animal models of stroke were included. Animals were divided into two groups: immunomodulators plus tPA (intervention group) or tPA alone (control group). The primary outcome was intracerebral hemorrhage, and the secondary outcomes included infarct volume and neurobehavioral score. Study quality was assessed by the checklist of CAMARADES. We used standardized mean difference (SMD) to assess the impact of interventions. Regression analysis and subgroup analysis were performed to identify potential sources of heterogeneity and evaluate the impact of the study characteristics. The evidence of publication bias was evaluated using trim and fill method and Egger’s test.

Results: We identified 22 studies that met our inclusion criteria involving 516 animals and 42 different comparisons. The median quality checklist score was seven of a possible 10 (interquartile range, 6–8). Immunomodulators improved cerebral hemorrhage (1.31 SMD, 1.09–1.52); infarct volume (1.35 SMD, 0.95–1.76), and neurobehavioral outcome (0.9 SMD, 0.67–1.13) in experimental stroke. Regression analysis and subgroup analysis indicated that control of temperature and time of assessment were important factors that influencing the efficacy of immunomodulators.

Conclusion: Our findings suggested that immunomodulators had a favorable effect on tPA-associated intracerebral hemorrhage, cerebral infarction, and neurobehavioral impairments in animal models of ischemic stroke.

YiQiFuMai Lyophilized Injection ameliorates tPA-induced hemorrhagic transformation by inhibiting cytoskeletal rearrangement associated with ROCK1 and NF-κB signaling pathways

ETHNOPHARMACOLOGICAL RELEVANCE

Thrombolytic therapy with tissue plasminogen activator (tPA) after ischemic stroke exacerbates blood-brain barrier (BBB) breakdown and leads to hemorrhagic transformation (HT). YiQiFuMai Lyophilized Injection (YQFM) is a modern preparation derived from Sheng-mai San (a traditional Chinese medicine). YQFM attenuates the BBB dysfunction induced by cerebral ischemia-reperfusion injury. However, whether YQFM can suppress tPA-induced HT remains unknown.

AIM OF THE STUDY

We investigated the therapeutic effect of YQFM on tPA-induced HT and explored the underlying mechanisms in vivo and in vitro to improve the safety of tPA use against stroke.

METHODS

Male C57BL/6J mice were subjected to 45 min of ischemia and 24 h of reperfusion. tPA (10 mg/kg) were infused 2 h after occlusion and YQFM (0.671 g/kg) was injected 2.5 h after occlusion. The in vitro effect of YQFM (100, 200, 400 μg/mL) on tPA (60 μg/mL)-induced dysfunction of the microvascular endothelial barrier in the brain following oxygen-glucose deprivation/reoxygenation (OGD/R) was observed in bEnd.3 cells.

RESULTS

YQFM suppressed tPA-induced high hemoglobin level in the brain, mortality, neurologic severity score, BBB permeability, expression and activation of matrix metalloproteinase (MMP)-9 and MMP-2, and degradation of tight-junction proteins. Furthermore, YQFM significantly blocked tPA-induced brain microvascular endothelial permeability and phosphorylation of Rho-associated kinase (ROCK)1, myosin light chain (MLC), cofilin and p65 in vivo and in vitro.

CONCLUSION

YQFM suppressed tPA-induced HT by inhibiting cytoskeletal rearrangement linked with ROCK-cofilin/MLC pathways and inhibiting the nuclear factor-kappa B pathway to ameliorate BBB damage caused by tPA.

Diabetes Mellitus/Poststroke Hyperglycemia: a Detrimental Factor for tPA Thrombolytic Stroke Therapy

Intravenous administration of tissue-type plasminogen activator (IV tPA) therapy has long been considered a mainstay in ischemic stroke management. However, patients respond to IV tPA therapy unequally with some subsets of patients having worsened outcomes after treatment. In particular, diabetes mellitus (DM) is recognized as a clinically important vascular comorbidity that leads to lower recanalization rates and increased risks of hemorrhagic transformation (HT). In this short-review, we summarize the recent advances in understanding of the underlying mechanisms involved in post-IV tPA worsening of outcome in diabetic stroke. Potential pathologic factors that are related to the suboptimal tPA recanalization in diabetic stroke include higher plasma plasminogen activator inhibitor (PAI)-1 level, diabetic atherogenic vascular damage, glycation of the tPA receptor annexin A2, and alterations in fibrin clot density. While factors contributing to the exacerbation of HT in diabetic stroke include hyperglycemia, vascular oxidative stress, and inflammation, tPA neurovascular toxicity and imbalance in extracellular proteolysis are discussed. Besides, impaired collaterals in DM also compromise the efficacy of IV tPA therapy. Additionally, several tPA combination approaches developed from experimental studies that may help to optimize IV tPA therapy are also briefly summarized. In summary, more research efforts are needed to improve the safety and efficacy of IV tPA therapy in ischemic stroke patients with DM/poststroke hyperglycemia.

Identification of Predictors for Hemorrhagic Transformation in Patients with Acute Ischemic Stroke After Endovascular Therapy Using the Decision Tree Model

Purpose

This study aimed to identify independent predictors for the risk of hemorrhagic transformation (HT) in arterial ischemic stroke (AIS) patients.

Methods

Consecutive patients with AIS due to large artery occlusion in the anterior circulation treated with mechanical thrombectomy (MT) were enrolled in a tertiary stroke center. Demographic and medical history data, admission lab results, and Circle of Willis (CoW) variations were collected from all patients.

Results

Altogether, 90 patients were included in this study; among them, 34 (37.8%) had HT after MT. The final pruned decision tree (DT) model consisted of collateral score and platelet to lymphocyte ratios (PLR) as predictors. Confusion matrix analysis showed that 82.2% (74/90) were correctly classified by the model (sensitivity, 79.4%; specificity, 83.9%). The area under the ROC curve (AUC) was 81.7%. The DT model demonstrated that participants with collateral scores of 2–4 had a 75.0% probability of HT. For participants with collateral scores of 0–1, if PLR at admission was <302, participants had a 13.0% probability of HT; otherwise, participants had an 75.0% probability of HT. The final adjusted multivariate logistic regression analysis indicated that collateral score 0–1 (OR, 10.186; 95% CI, 3.029–34.248; p < 0.001), PLR (OR, 1.005; 95% CI, 1.001–1.010; p = 0.040), and NIHSS at admission (OR, 1.106; 95% CI, 1.014–1.205; p = 0.022) could be used to predict HT. The AUC for the model was 0.855, with 83.3% (75/90) were correctly classified (sensitivity, 79.4%; specificity, 87.3%). Less patients with HT achieved independent outcomes (mRS, 0–2) in 90 days (20.6% vs. 64.3%, p < 0.001). Rate of poor outcomes (mRS, 4–6) was significantly higher in patients with HT (73.5% vs. 19.6%; p < 0.001).

Conclusion

Both the DT model and multivariate logistic regression model confirmed that the lower collateral status and the higher PLR were significantly associated with an increased risk for HT in AIS patients after MT. PLR may be one of the cost-effective and practical predictors for HT. Further prospective multicenter studies are needed to validate our findings.

Inhibition of PI3Kγ by AS605240 plus low-dose tissue plasminogen activator (tPA) combination improves thrombolytic therapy in a rat model of embolic stroke

Our previous study showed that PI3Kγ inhibition with AS605240 plus a standard rat-dose tPA (10 mg/kg) combination attenuates delayed tPA-induced brain hemorrhage and ameliorates acute stroke injury 3 days after ischemic stroke in rats. The purpose of this study was to investigate whether combining AS605240 with tPA can enhance thrombolytic efficacy, so that lower doses of tPA can be applied to improve long-term outcome after ischemic stroke. The results showed that AS605240 plus low-dose tPA (5 mg/kg) combination therapy at 4 h after stroke onset significantly reduced infarct volume and neurological deficits at 24 h after stroke compared with saline, AS605240 or low-dose tPA alone group. Importantly, the combination therapy significantly reduced the delayed tPA-associated brain hemorrhage. Moreover, the combination therapy significantly decreased the size of the residual embolus within the middle cerebral artery, which was associated with a decrease in plasma plasminogen activator inhibitor-1 (PAI-1) activity compared with saline and tPA alone. Finally, AS605240 plus low-dose tPA combination improved long-term outcome for at least 35 days after stroke compared with the saline-treated group. Taken together, these findings suggest that PI3Kγ inhibition with AS605240 might act as an adjunct approach for enhancing tPA thrombolytic efficacy in acute ischemic stroke.

Phosphoinositide 3-kinase inhibitor AS605240 ameliorates streptozotocin-induced Alzheimer's disease like sporadic dementia in experimental rats

The quest for chemical entities able to curb the action of the phosphoinositide 3-kinase, (PI3K)/protein kinase B (AKT) signaling pathways is evolving as a potential therapeutic strategy for the treatment and/or prevention of neurodegenerative disorders including Alzheimer's disease (AD). In this study, the effects of a PI3K inhibitor, AS605240 on cognitive dysfunction and antioxidative defense parameters against intra-cerebroventricular-streptozotocin (ICV-STZ)-induced rat model of sporadic AD was evaluated. ICV administration of a single dose of STZ (3 mg/kg) was performed to induce behavioral and biochemical changes in rats using the stereotaxic technique. Animals were administered with varying doses of AS605240 (5, 10 and 15 mg/kg) orally, 1 h before ICV-STZ on day 1 and continued once daily for four weeks. The behavioral parameters (passive avoidance and Morris water maze), antioxidative defense parameters, amyloid-beta (Aβ) protein expression by Western blotting and immunostaining technique were estimated in brain tissue. AS605240 dose-dependently and significantly (p < 0.05 and p < 0.01 and p < 0.001) improved ICV-STZ-induced cognitive impairment and attenuated the altered antioxidative related parameters including superoxide dismutase, lipid peroxidation, glutathione and nitrite levels. Further, the increased Aβ protein expression levels in brain tissue were markedly restored with AS605240 treatment. In conclusion, our study demonstrated that AS605240 exhibited immense potential in attenuating STZ-induced sporadic AD features in rats and may be developed as a therapeutic agent in the treatment and management of sporadic AD.

Induction of Neuronal PI3Kγ Contributes to Endoplasmic Reticulum Stress and Long-Term Functional Impairment in a Murine Model of Traumatic Brain Injury

Phosphoinositide 3-kinase γ (PI3Kγ) expressed in immune cells is linked to neuroinflammation in several neurological diseases. However, the expression and role of PI3Kγ in preclinical traumatic brain injury (TBI) have not been investigated. In WT mice, we found that TBI induced rapid and extensive expression of PI3Kγ in neurons within the perilesional cortex and the ipsilateral hippocampal subfields (CA1, CA3), which peaked between 1 and 3 days and declined significantly 7 days after TBI. Intriguingly, the induction of neuronal PI3Kγ in these subregions of the brain spatiotemporally coincided with both the TBI-induced activation of the neuronal ER stress pathway (p-eIF2α, ATF4, and CHOP) and neuronal cell death (marked by TUNEL-positive neurons) 3 days after TBI. Further, we show that the absence of PI3Kγ in knockout mice profoundly reduced the TBI-induced activation of the ER stress pathway and neuronal cell death. White matter disruption is a better predictor of long-term clinical outcomes than focal lesion size. We show that PI3Kγ deficiency not only reduced brain tissue loss but also alleviated white matter injury (determined by axonal injury and demyelination) up to 28 days after TBI. Importantly, PI3Kγ-knockout mice exhibited greater functional recovery including forepaw use, sensorimotor balance and coordination, and spatial learning and memory up to 28 days after TBI. These results unveil a previously unappreciated role for neuronal PI3Kγ in the regulation of ER stress associated with neuronal cell death, white matter damage, and long-term functional impairment after TBI.