Sophoricoside ameliorates cerebral ischemia-reperfusion injury dependent on activating AMPK

AIMS

Ischemic stroke accounts for 87% of all strokes, and its death and disability bring a huge burden to society. Brain injury caused by ischemia-reperfusion (I/R) is also a major difficulty in clinical treatment and prognosis. Sophoricoside (SOP) is an isoflavone glycoside isolated from the seed of medical herb Sophora japonica L. Previously, SOP was found to be effective in anti-inflammation and glucose-lipid metabolism-related diseases. In order to investigate whether SOP has a regulatory effect on cerebral I/R injury, we conducted this study.

METHODS

Here, by application of SOP into MCAO (transient middle cerebral artery occlusion)-induced mice and OGD/R (oxygen glucose deprivation/reperfusion)-induced primary neurons, the regulation effects of SOP was analyzed by detecting neurological score of post-stroke mice, phenotypes of brains and brain sections, cell viabilities, and apoptosis- and inflammation-regulation. RNA sequencing and molecular biology experiments were performed to explore the mechanism of SOP regulating cerebral I/R injury.

RESULTS

SOP administration decreased the infarct size, neurological deficit score, neuronal cell injury, inflammation and apoptosis. Mechanistically, SOP exerted its protective effect by activating the AMP-activated protein kinase (AMPK) signaling pathway.

CONCLUSION

SOP inhibits cerebral I/R injury by promoting the phosphorylation of AMPK.

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.

ADAMTS13 deficiency exacerbates neuroinflammation by targeting matrix metalloproteinase-9 in ischemic brain injury

Our design aimed to explore the potential involvement of matrix metalloproteinase-9 (MMP-9) in the inflammatory response associated with acute ischemic stroke (AIS). We also aimed to preliminarily examine the potential impact of a disintegrin-like and metalloprotease with thrombospondin type I repeats-13 (ADAMTS13) on MMP-9 in AIS. We conducted oxygen-glucose deprivation models of microglia cells and mice models of AIS with middle cerebral artery occlusion (MCAO). We assessed the expression pattern of MMP-9 with western blotting (WB) and real-time quantitative PCR both in vivo and in vitro. MMP-9 downregulation was achieved by using ACE inhibitors such as trandolapril. For the MCAO model, we used ADAMTS13-deficient mice. We then evaluated the related neurological function scores, cerebral edema and infarct volume. The levels of inflammation-related proteins, such as COX2 and iNOS, were assessed using WB, and the expression of inflammatory cytokines was measured via enzyme-linked immuno sorbent assay in vivo. Our findings indicated that MMP-9 was up-regulated while ADAMTS13 was down-regulated in the MCAO model. Knockdown of MMP-9 reduced both inflammation and ischemic brain injury. ADAMTS13 prevented brain damage, improved neurological function and decreased the inflammation response in mice AIS models. Additionally, ADAMTS13 alleviated MMP-9-induced neuroinflammation in vivo. It showed that ADAMTS13 deficiency exacerbated ischemic brain injury through an MMP-9-dependent inflammatory mechanism. Therefore, the ADAMTS13-MMP-9 axis could have therapeutic potential for the treatment of AIS.

Movement disorders following mechanical thrombectomy resulting in ischemic lesions of the basal ganglia: An emerging clinical entity

BACKGROUND AND PURPOSE

Post-stroke movement disorders (PMDs) following ischemic lesions of the basal ganglia (BG) are a known entity, but data regarding their incidence are lacking. Ischemic strokes secondary to proximal middle cerebral artery (MCA) occlusion treated with thrombectomy represent a model of selective damage to the BG. The aim of this study was to assess the prevalence and features of movement disorders after selective BG ischemia in patients with successfully reperfused acute ischemic stroke (AIS).

METHODS

We enrolled 64 consecutive subjects with AIS due to proximal MCA occlusion treated with thrombectomy. Patients were clinically evaluated by a movement disorders specialist for PMDs onset at baseline, and after 6 and 12 months.

RESULTS

None of the patients showed an identifiable movement disorder in the subacute phase of the stroke. At 6 and 12 months, respectively, 7/25 (28%) and 7/13 (53.8%) evaluated patients developed PMDs. The clinical spectrum of PMDs encompassed parkinsonism, dystonia and chorea, either isolated or combined. In most patients, symptoms were contralateral to the lesion, although a subset of patients presented with bilateral involvement and prominent axial signs.

CONCLUSION

Post-stroke movement disorders are not uncommon in long-term follow-up of successfully reperfused AIS. Follow-up conducted by a multidisciplinary team is strongly advisable in patients with selective lesions of the BG after AIS, even if asymptomatic at discharge.

Echinatin protects from ischemic brain injury by attenuating NLRP3-related neuroinflammation

BACKGROUND

Microglia-mediated neuroinflammation is the major contributor to the secondary brain injury of ischemic stroke. NLRP3 is one of the major components of ischemia-induced microglial activation. Echinatin, a chalcone found in licorice, was reported to have the activity of anti-inflammation and antioxidant. However, the relative study of echinatin in microglia or ischemic stroke is still unclear.

METHODS

We intravenously injected echinatin or vehicle into adult ischemic male C57/BL6J mice induced by 60-min transient middle cerebral artery occlusion (tMCAO). The intraperitoneal injection was performed 4.5 h after reperfusion and then daily for 2 more days. Infarct size, blood brain barrier (BBB) leakage, neurobehavioral tests, and microglial-mediated inflammatory reaction were examined to assess the outcomes of echinatin treatment. LPS and LPS/ATP stimulation on primary microglia were used to explore the underlying anti-inflammatory mechanism of echinatin.

RESULTS

Echinatin treatment efficiently decreased the infarct size, alleviated blood brain barrier (BBB) damage, suppressed microglial activation, reduced the production of inflammatory factors (e.g., IL-1β, IL-6, IL-18, TNF-α, iNOS, COX2), and relieved post-stroke neurological defects in tMCAO mice. Mechanistically, we found that echinatin could suppress the NLRP3 assembly and reduce the production of inflammatory mediators independently of NF-κB and monoamine oxidase (MAO).

CONCLUSION

Based on our study, we have identified echinatin as a promising therapeutic strategy for the treatment of ischemic stroke.

Intranasal Delivery of Mitochondria Attenuates Brain Injury by AMPK and SIRT1/PGC-1α Pathways in a Murine Model of Photothrombotic Stroke

Ischemic stroke is one of the major causes of morbidity and mortality worldwide. Mitochondria play a vital role in the pathological processes of cerebral ischemic injury, but its transplantation and underlying mechanisms remain unclear. In the present study, we examined the effects of mitochondrial therapy on the modulation of AMPK and SIRT1/PGC-1α signaling pathway, oxidative stress, and NLRP3 inflammasome activation after photothrombotic ischemic stroke (pt-MCAO). The adult male mice were subjected to the pt-MCAO in which the proximal-middle cerebral artery was exposed with a 532-nm laser beam for 4 min by retro-orbital injection of a photosensitive dye (Rose Bengal: 15 mg/kg) before the laser light exposure and isolated mitochondria (100 μg protein) were administered intranasally at 30 min, 24 h, and 48 h following post-stroke. After 72 h, mice were tested for neurobehavioral outcomes and euthanized for infarct volume, brain edema, and molecular analysis. First, we found that mitochondria therapy significantly decreased brain infarct volume and brain edema, improved neurological dysfunction, attenuated ischemic stroke-induced oxidative stress, and neuroinflammation. Second, mitochondria treatment inhibited NLRP3 inflammasome activation. Finally, mitochondria therapy accelerated p-AMPKα(Thr172) and PGC-1α expression and resorted SIRT1 protein expression levels in pt-MCAO mice. In conclusion, our results demonstrate that mitochondria therapy exerts neuroprotective effects by inhibiting oxidative damage and inflammation, mainly dependent on the heightening activation of the AMPK and SIRT1/PGC-1α signaling pathway. Thus, intranasal delivery of mitochondria might be considered a new therapeutic strategy for ischemic stroke treatment.

Social isolation initiated post-weaning augments ischemic brain injury by promoting pro-inflammatory responses

Social isolation is associated with poor stroke outcome, but the underlying molecular mechanisms were largely unknown. In male Balb/C mice exposed to transient middle cerebral artery occlusion (MCAo), we examined the effects of social isolation initiated post-weaning on ischemic injury, cytokine/chemokine responses and cell signaling using a broad panel of techniques that involved immunocytochemistry, cytokine/chemokine array and Western blots. Social isolation initiated post-weaning elevated infarct size, brain edema and neuronal injury in the ischemic brain tissue 3 days after MCAo, and increased microglia/ macrophage and leukocyte accumulation. In line with the increased immune cell recruitment, levels of several proinflammatory cytokines (e.g., IL-1α, IL-1β, IL-13, IL-17, TNF-α, IFN-γ), chemokines (e.g., CCL3, CCL4, CCL12, CXCL2, CXCL9, CXCL12) and adhesion molecules (i.e., ICAM-1) were increased in the ischemic brain tissue of socially isolated compared with paired housing mice, whereas levels of selected cytokines (IL-5, IL-6, IL-16) and colony-stimulating factors (G-CSF, GM-CSF) were reduced. The activity of the transcription factor nuclear factor-ĸB (NF-ĸB), which promotes cell injury via pro-inflammatory responses, was increased by social isolation, whereas that of nuclear factor erythroid related factor-2 (Nrf-2), which mediates anti-oxidative responses under oxidative stress conditions, was reduced. Our study shows that social isolation profoundly alters post-ischemic cell signaling in a way promoting pro-inflammatory responses. Our results highlight the importance of social support in preventing deleterious health effects of social isolation.

PI3Kδ inhibition alleviates the brain injury during cerebral ischemia reperfusion via suppressing pericyte contraction in a TNF-α dependent manner

The pericytes (PCs) surrounding capillaries are vital regulators of capillary constriction. Persistent PC contraction results in the increased capillary constriction, therefore leading to the impaired cerebral blood flow (CBF) recovery after reperfusion and worsening the clinical outcomes in stroke patients. However, the potential determinants of PC functions during ischemia/reperfusion are poorly understood. Phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit Delta (PIK3CD/PI3Kδ) is a crucial factor involved with neuronflammation during ischemic stroke. PI3Kδ has shown the expression in PCs, while its effect on PC functions has not been explored yet. In this study, a rodent ischemia/reperfusion model was established in C57BL/6 mice via transient middle cerebral artery occlusion and reperfusion (MCAO/R). The PI3Kδ expression in ischemic penumbra was remarkably upregulated following MCAO/R induction. PI3Kδ inhibitor CAL-101 improved the CBF recovery, ischemic brain injury, and suppressed capillary constriction in MCAO/R mice. Besides, the production of tumor necrosis factor alpha (TNF-α), an inducer for tissue injury, and the expression of transient receptor potential vanilloid type 2 (TRPV2), a channel protein permitting calcium (Ca2+) uptake, were significantly reduced in ischemic penumbra after CAL-101 treatment. In vitro, oxygen-glucose deprivation and reoxygenation (OGD/R) enhanced the expression of PI3Kδ and TRPV2 in primary mouse PCs. CAL-101 suppressed the TNF-α-induced TRPV2 expression in OGD/R-treated PCs, thus inhibiting the Ca2+ uptake and PC contraction. Collectively, this study suggests that PI3Kδ is a critical regulator of PC function during ischemic stroke.

Mechanism of astragaloside IV regulating NLRP3 through LOC102555978 to attenuate cerebral ischemia reperfusion induced microglia pyroptosis

Astragaloside IV(ASⅣ), the main component of Radix Astragali, has been used to treat cerebral ischemia reperfusion injury (CIRI). However, the molecular mechanism of ASIV in CIRI needs to be further elucidated. Long non-coding RNA (lncRNA) is considered to be an important kind of regulatory molecule in CIRI. In this work, the biological effect and molecular mechanism of ASIV in CIRI through lncRNA were analyzed by using rat middle cerebral artery occlusion and reperfusion (MCAO/R) model and primary rat microglia (RM) cells oxygen and glucose deprivation/reoxygenation (OGD/R) model. The neurological deficit score was evaluated, the volume of cerebral infarction was calculated, and pyroptosis related molecules were detected by qPCR and western blot. Then, high-throughput sequencing was performed in sham and MCAO/R groups. The competitive endogenous RNA (ceRNA) networks associated with pyroptosis were constructed by functional enrichment analysis. CCK-8 detection of cell survival rate, qPCR and western blot were used to determine the specific molecular mechanism of ASⅣ through ceRNA in vitro. Results showed thatASⅣ could decrease the neurological deficit score, reduce the volume of cerebral infarction, inhibit inflammatory reaction and pyroptosis in MCAO/R model rats. Next, the ceRNA network was established, including the LOC102555978/miR-3584-5p/NLRP3 regulatory network. In vitro experiments showed that LOC102555978 promotes NLRP3 mediated pyroptosis of RM cells through sponge adsorption of miR-3584-5p, which may provide a potential therapeutic target for post-CIRI inflammation regulation. ASⅣ could inhibit pyroptosis of RM cells by down-regulating LOC102555978. LOC102555978/miR-3584-5p/NLRP3 may be the molecular mechanism of ASⅣ's CIRI protective effect.

Dihydroergotamine protects against ischemic stroke by modulating microglial/macrophage polarization and inhibiting inflammation in mice

OBJECTIVES

The search for drugs that can protect the brain tissue and reduce nerve damage in acute ischemic stroke has emerged as a research hotspot. We investigated the potential protective effects and mechanisms of action of dihydroergotamine against ischemic stroke.

METHODS

C57BL/6 mice were subjected to middle cerebral artery occlusion (MCAO), and dihydroergotamine at a dose of 10 mg/kg/day was intraperitoneally injected for 14 days. Adhesive removal and beam walking tests were conducted 1, 3, 5, 7, 10, and 14 days after MCAO surgery. Thereafter, the mechanism by which dihydroergotamine regulates microglia/macrophage polarization and inflammation and imparts ischemic stroke protection was studied using enzyme-linked immunosorbent assay, immunofluorescence staining, and western blotting.

RESULTS

From the perspective of a drug repurposing strategy, dihydroergotamine was found to inhibit oxygen-glucose deprivation damage to neurons, significantly improve cell survival rate, and likely exert a protective effect on ischemic brain injury. Dihydroergotamine significantly improved neural function scores and survival rates and reduced brain injury severity in mice. Furthermore, dihydroergotamine manifests its protective effect on ischemic brain injury by reducing the expression of TNF-α and IL-1β in mouse ischemic brain tissue, inhibiting the polarization of microglia/macrophage toward the M1 phenotype and promoting polarization toward the M2 phenotype.

CONCLUSION

This study is the first to demonstrate the protective effect of dihydroergotamine, a first-line treatment for migraine, against ischemic nerve injury in vitro and in vivo.

Enhanced angiogenesis in the thalamus induced by a novel TSPO ligand ameliorates cognitive deficits after focal cortical infarction

Neuronal loss in the ipsilateral thalamus after focal cortical infarction participates in post-stroke cognitive deficits, and enhanced angiogenesis in the thalamus is expected to reduce neuronal damage. We hypothesize that novel translocator protein (TSPO) ligand, 2-Cl-MGV-1, can promote angiogenesis, attenuate neuronal loss in the thalamus, and ameliorate post-stroke cognitive deficits. Cortical infarction was induced by distal middle cerebral artery occlusion (dMCAO) in stroke-prone renovascular hypertensive rats. 2-Cl-MGV-1 or dimethyl sulfoxide was administered 24 h after dMCAO and then for 6 or 13 days. Spatial learning and memory were assessed using the Morris water maze. Neuronal loss, TSPO expression, angiogenesis, and intrinsic pathway were determined by immunofluorescence and immunoblotting 7 and 14 days after dMCAO. Cortical infarction caused post-stroke cognitive deficits and secondary neuronal loss with gliosis in the ipsilateral thalamus within 14 days of dMCAO. Increased angiogenesis and elevated expression of vascular TSPO were detected in the ipsilateral thalamus, and treatment with 2-Cl-MGV-1 enhanced angiogenesis by stimulating the PI3K-AKT-mTOR pathway. The effects of 2-Cl-MGV-1 on angiogenesis coincided with reduced neuronal loss in the thalamus and contributed to improvements in post-stroke cognitive deficits. Our findings suggest that 2-Cl-MGV-1 stimulates angiogenesis, ameliorates neuronal loss in the thalamus, and improves post-stroke cognitive deficits.

Intracerebroventricular BDNF infusion may reduce cerebral ischemia/reperfusion injury by promoting autophagy and suppressing apoptosis

Here, it was aimed to investigate the effects of intracerebroventricular (ICV) Brain Derived Neurotrophic Factor (BDNF) infusion for 7 days following cerebral ischemia (CI) on autophagy in neurons in the penumbra. Focal CI was created by the occlusion of the right middle cerebral artery. A total of 60 rats were used and divided into 4 groups as Control, Sham CI, CI and CI + BDNF. During the 7-day reperfusion period, aCSF (vehicle) was infused to Sham CI and CI groups, and BDNF infusion was administered to the CI + BDNF group via an osmotic minipump. By the end of the 7th day of reperfusion, Beclin-1, LC3, p62 and cleaved caspase-3 protein levels in the penumbra area were evaluated using Western blot and immunofluorescence. BDNF treatment for 7 days reduced the infarct area after CI, induced the autophagic proteins Beclin-1, LC3 and p62 and suppressed the apoptotic protein cleaved caspase-3. Furthermore, rotarod and adhesive removal test times of BDNF treatment started to improve from the 4th day, and the neurological deficit score from the 5th day. ICV BDNF treatment following CI reduced the infarct area by inducing autophagic proteins Beclin-1, LC3 and p62 and inhibiting the apoptotic caspase-3 protein while its beneficial effects were apparent in neurological tests from the 4th day.

Integrated network pharmacology, molecular docking and pharmacodynamic study reveals protective effects and mechanisms of corilagin against cerebral ischemia-induced injury

BACKGROUND

Stroke is one of the leading causes of death and long-term disability worldwide. Previous studies have found that corilagin has antioxidant, anti-inflammatory, anti-atherosclerotic and other pharmacological activities and has a protective effect against cardiac and cerebrovascular injury.

OBJECTIVES

The aim of this study was to investigate the protective effects of corilagin against ischemic stroke and to elucidate the underlying molecular mechanisms using network pharmacology, molecular docking, and animal and cell experiments.

METHODS

We investigated the potential of corilagin to ameliorate cerebral ischemia-reperfusion injury using in vivo rat middle cerebral artery occlusion/reperfusion (MCAO/R) and in vitro oxygen-glucose deprivation/reoxygenation (OGD/R) models.

RESULTS

Our results suggest that corilagin may exert its anti-ischemic stroke effect by interacting with 92 key targets, including apoptosis-associated proteins (Bcl-2, Bax, caspase-3) and PI3K/Akt signaling pathway-related proteins. In vivo and in vitro experiments showed that corilagin treatment improved neurological deficits, attenuated cerebral infarct volume, and mitigated neuronal damage in MCAO/R rats. Corilagin treatment also enhanced the survival of PC12 cells exposed to OGD/R, reduced the rate of LDH leakage, inhibited cell apoptosis, and activated the PI3K/Akt signaling pathway. Importantly, the effects of corilagin on the PI3K/Akt signaling pathway and apoptosis-associated proteins were reversed by the PI3K-specific inhibitor LY294002.

CONCLUSIONS

These results indicate that the molecular mechanism of the anti-ischemic effect of corilagin involves inhibiting neuronal apoptosis and activating the PI3K/Akt signaling pathway. These findings provide a theoretical and experimental basis for the further development and application of corilagin as a potential anti-ischemic stroke agent.

SIRT5 Regulates Ferroptosis through the Nrf2/HO-1 Signaling Axis to Participate in Ischemia-Reperfusion Injury in Ischemic Stroke

This work aimed to study the role and mechanism of SIRT5 regulation of ferroptosis in cerebral ischemia-reperfusion (I/R) injury. A model of middle cerebral artery occlusion in rats was prepared using the method of thread occlusion. The ferroptosis inhibitor was injected intraperitoneally while the SIRT5 interfering lentivirus were injected into the brain, and neurological disorders were scored in the rats. TTC staining was used to detect infarct volume, and immunohistochemistry was used to detect the expression of SIRT5 in tissues. Rat hippocampal neuronal cells H19-7 were transduced with SIRT5 interfering lentivirus and ferroptosis was induced using erastin. The CCK8 detection kit was used to detect cell viability. Commercial kits were used to detect levels of iron ions, ROS, MDA, SOD, and inflammatory factor (TNF-α and IL-6) in brain tissue or cell supernatant. Western blot was used to detect the expression changes of ferroptosis related proteins GPX4, Nrf2, and HO-1 in tissues or cells. Compared with the sham group, the MCAO model group showed higher levels of neurological impairment score, increased cerebral infarction volume, iron ions, inflammatory factors, and oxidative stress levels in rats. Compared with the MCAO group, the MCAO + fer-1 group exhibited lower levels of neurological impairment scores, cerebral infarction volume, decreased iron ions, inflammatory factors, and oxidative stress levels in rats. Meanwhile, compared with the MCAO + DMSO/LV-shRNA group, the MCAO + fer-1/LV-shSIRT5 group showed a significant decrease in neurological impairment scores, cerebral infarction volume, iron ions, inflammatory factors, and oxidative stress levels in rats. In vitro experiments have found that LV-shSIRT5 can prevent erastin-induced cell ferroptosis. In summary, SIRT5 regulates ferroptosis through the Nrf2/HO-1 signaling axis to participate in ischemia-reperfusion injury in ischemic stroke.

Prior Thrombectomy Does Not Affect the Surgical Complication Rate of Decompressive Hemicraniectomy in Patients with Malignant Ischemic Stroke

BACKGROUND

Even though mechanical recanalization techniques have dramatically improved acute stroke care since the pivotal trials of decompressive hemicraniectomy for malignant courses of ischemic stroke, decompressive hemicraniectomy remains a mainstay of malignant stroke treatment. However, it is still unclear whether prior thrombectomy, which in most cases is associated with application of antiplatelets and/or anticoagulants, affects the surgical complication rate of decompressive hemicraniectomy and whether conclusions derived from prior trials of decompressive hemicraniectomy are still valid in times of modern stroke care.

METHODS

A total of 103 consecutive patients who received a decompressive hemicraniectomy for malignant middle cerebral artery infarction were evaluated in this retrospective cohort study. Surgical and functional outcomes of patients who had received mechanical recanalization before surgery (thrombectomy group, n = 49) and of patients who had not received mechanical recanalization (medical group, n = 54) were compared.

RESULTS

The baseline characteristics of the two groups did significantly differ regarding preoperative systemic thrombolysis (63.3% in the thrombectomy group vs. 18.5% in the medical group, p < 0.001), the rate of hemorrhagic transformation (44.9% vs. 24.1%, p = 0.04) and the preoperative Glasgow Coma Score (median of 7 in the thrombectomy group vs. 12 in the medical group, p = 0.04) were similar to those of prior randomized controlled trials of decompressive hemicraniectomy. There was no significant difference in the rates of surgical complications (10.2% in the thrombectomy group vs. 11.1% in the medical group), revision surgery within the first 30 days after surgery (4.1% vs. 5.6%, respectively), and functional outcome (median modified Rankin Score of 4 at 5 and 14 months in both groups) between the two groups.

CONCLUSIONS

A prior mechanical recanalization with possibly associated systemic thrombolysis does not affect the early surgical complication rate and the functional outcome after decompressive hemicraniectomy for malignant ischemic stroke. Patient characteristics have not changed significantly since the introduction of mechanical recanalization; therefore, the results from former large randomized controlled trials are still valid in the modern era of stroke care.

Novel subsets of peripheral immune cells associated with promoting stroke recovery in mice

AIMS

Peripheral immune cells infiltrating into the brain trigger neuroinflammation after an ischemic stroke. Partial immune cells reprogram their function for neural repair. Which immune cells promote ischemic brain recovery needs further identification.

METHODS

We performed single-cell transcriptomic profiling of CD45high immune cells isolated from the ischemic hemisphere at subacute (5 days) and chronic (14 days) stages after ischemic stroke.

RESULTS

A subset of phagocytic macrophages was associated with neuron projection regeneration and tissue remodeling. We also identified a unique type of T cells with highly expressed macrophage markers, including C1q, Apoe, Hexb, and Fcer1g, which showed high abilities in tissue remodeling, myelination regulation, wound healing, and anti-neuroinflammation. Moreover, natural killer cells decreased cytotoxicity and increased energy and metabolic function in the chronic stage after ischemic stroke. Two subgroups of neutrophils upregulated CCL signals to recruit peripheral immune cells and released CXCL2 to keep self-recruiting at the chronic stage.

CONCLUSIONS

We identified subsets of peripheral immune cells that may provide potential therapeutic targets for promoting poststroke recovery.

Retinoic acid attenuates ischemic injury-induced activation of glial cells and inflammatory factors in a rat stroke model

Stroke is a leading cause of death and long-term disability which can cause oxidative damage and inflammation of the neuronal cells. Retinoic acid is an active metabolite of vitamin A that has various beneficial effects including antioxidant and anti-inflammatory effects. In this study, we investigated whether retinoic acid modulates oxidative stress and inflammatory factors in a stroke animal model. A middle cerebral artery occlusion (MCAO) was performed on adult male rats to induce focal cerebral ischemia. Retinoic acid (5 mg/kg) or vehicle was injected into the peritoneal cavity for four days before MCAO surgery. The neurobehavioral tests were carried out 24 h after MCAO and cerebral cortex tissues were collected. The cortical damage was assessed by hematoxylin-eosin staining and reactive oxygen species assay. In addition, Western blot and immunohistochemical staining were performed to investigate the activation of glial cells and inflammatory cytokines in MCAO animals. Ionized calcium-binding adapter molecule-1 (Iba-1) and glial fibrillary acidic protein (GFAP) were used as markers of microglial and astrocyte activation, respectively. Tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were used as representative pro-inflammatory cytokines. Results showed that MCAO damage caused neurobehavioral defects and histopathological changes in the ischemic region and increased oxidative stress. Retinoic acid treatment reduced these changes caused by MCAO damage. We detected increases in Iba-1 and GFAP in MCAO animals treated with vehicle. However, retinoic acid alleviated increases in Iba-1 and GFAP caused by MCAO damage. Moreover, MCAO increased levels of nuclear factor-κB and pro-inflammatory cytokines, including TNF-α and IL-1β. Retinoic acid alleviated the expression of these inflammatory proteins. These findings elucidate that retinoic acid regulates microglia and astrocyte activation and modulates pro-inflammatory cytokines. Therefore, this study suggests that retinoic acid exhibits strong antioxidant and anti-inflammatory properties by reducing oxidative stress, inhibiting neuroglia cell activation, and preventing the increase of pro-inflammatory cytokines in a 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.

Involvement of CKS1B in the anti-inflammatory effects of cannabidiol in experimental stroke models

We have previously demonstrated that treatment with cannabidiol (CBD) ameliorates mitochondrial dysfunction and attenuates neuronal injury in rats following cerebral ischemia. However, the role of CBD in the progression of ischemic stroke-induced inflammation and the molecules involved remain unclear. Here, we found that CBD suppressed the production of interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α), reduced the activation of microglia, ameliorated mitochondrial deficits, and decreased the phosphorylation of nuclear factor κ-B (NF-κB) in BV-2 cells subjected to oxygen-glucose deprivation/reoxygenation (OGD/R). Cyclin-dependent kinase regulatory subunit 1B (CKS1B) expression was decreased in BV-2 cells following OGD/R and this reduction was blocked by treatment with CBD. Knockdown of CKS1B increased the activation of microglia and enhanced the production of IL-1β and TNF-α in BV-2 cells treated with CBD. Moreover, CKS1B knockdown exacerbated mitochondrial deficits and increased NF-κB phosphorylation. CBD treatment also ameliorated brain injury, reduced neuroinflammation, and enhanced the protein levels of mitochondrial transcription factor A and CKS1B in rats following middle cerebral artery occlusion/reperfusion. These data identify CKS1B as a novel regulator of neuroinflammation; and reveals its involvement in the anti-inflammatory effects of CBD. Interventions targeting CKS1B expression are potentially promising for treating in ischemic stroke.

Intranasal administration of recombinant prosaposin attenuates neuronal apoptosis through GPR37/PI3K/Akt/ASK1 pathway in MCAO rats

Studies have reported that Prosaposin (PSAP) is neuroprotective in cerebrovascular diseases. We hypothesized that PSAP would reduce infarct volume by attenuating neuronal apoptosis and promoting cell survival through G protein-coupled receptor 37(GPR37)/PI3K/Akt/ASK1 pathway in middle cerebral artery occlusion (MCAO) rats. Two hundred and thirty-five male and eighteen female Sprague-Dawley rats were used. Recombinant human PSAP (rPSAP) was administered intranasally 1 h (h) after reperfusion. PSAP small interfering ribonucleic acid (siRNA), GPR37 siRNA, and PI3K specific inhibitor LY294002 were administered intracerebroventricularly 48 h before MCAO. Infarct volume, neurological score, immunofluorescence staining, Western blot, Fluoro-Jade C (FJC) and TUNEL staining were examined. The expression of endogenous PSAP and GPR37 were increased after MCAO. Intranasal administration of rPSAP reduced brain infarction, neuronal apoptosis, and improved both short- and long-term neurological function. Knockdown of endogenous PSAP aggravated neurological deficits. Treatment with exogenous rPSAP increased PI3K expression, Akt and ASK1 phosphorylation, and Bcl-2 expression; phosphorylated-JNK and Bax levels were reduced along with the number of FJC and TUNEL positive neurons. GPR37 siRNA and LY294002 abolished the anti-apoptotic effect of rPSAP at 24 h after MCAO. In conclusion, rPSAP attenuated neuronal apoptosis and improved neurological function through GPR37/PI3K/Akt/ASK1 pathway after MCAO in rats. Therefore, further exploration of PSAP as a potential treatment option in ischemic stroke is warranted.

Inhibition of EphA4 reduces vasogenic edema after experimental stroke in mice by protecting the blood-brain barrier integrity

Cerebral vasogenic edema, a severe complication of ischemic stroke, aggravates neurological deficits. However, therapeutics to reduce cerebral edema still represent a significant unmet medical need. Brain microvascular endothelial cells (BMECs), vital for maintaining the blood-brain barrier (BBB), represent the first defense barrier for vasogenic edema. Here, we analyzed the proteomic profiles of the cultured mouse BMECs during oxygen-glucose deprivation and reperfusion (OGD/R). Besides the extensively altered cytoskeletal proteins, ephrin type-A receptor 4 (EphA4) expressions and its activated phosphorylated form p-EphA4 were significantly increased. Blocking EphA4 using EphA4-Fc, a specific and well-tolerated inhibitor shown in our ongoing human phase I trial, effectively reduced OGD/R-induced BMECs contraction and tight junction damage. EphA4-Fc did not protect OGD/R-induced neuronal and astrocytic death. However, administration of EphA4-Fc, before or after the onset of transient middle cerebral artery occlusion (tMCAO), reduced brain edema by about 50%, leading to improved neurological function recovery. The BBB permeability test also confirmed that cerebral BBB integrity was well maintained in tMCAO brains treated with EphA4-Fc. Therefore, EphA4 was critical in signaling BMECs-mediated BBB breakdown and vasogenic edema during cerebral ischemia. EphA4-Fc is promising for the treatment of clinical post-stroke edema.

Transcutaneous electrical acupoint stimulation attenuated neuroinflammation and oxidative stress by activating SIRT1-induced signaling pathway in MCAO/R rat models

BACKGROUND

Silent information regulator 1 (SIRT1) plays a beneficial role in cerebral ischemic injury. Previous reports have demonstrated that transcutaneous electrical acupoint stimulation (TEAS) exerts a beneficial effect on ischemic stroke; however, whether SIRT1 participates in the underlying mechanism for the neuroprotective effects of TEAS against ischemic brain damage has not been confirmed.

METHODS

The rat models of middle cerebral artery occlusion/reperfusion (MCAO/R) were utilized in the current experiment. After MCAO/R surgery, rats in TEAS, EC and EX group received TEAS intervention with or without the injection of EX527, the SIRT1 inhibitor. Neurological deficit scores, infarct volume, hematoxylin eosin (HE) staining and apoptotic cell number were measured. The results of RNA sequencing were analyzed to determine the differential expression changes of genes among sham, MCAO and TEAS groups, in order to investigate the possible pathological processes involved in cerebral ischemia and explore the protective mechanisms of TEAS. Moreover, oxidative stress markers including MDA, SOD, GSH and GSH-Px were measured with assay kits. The levels of the proinflammatory cytokines, such as IL-6, IL-1β and TNF-α, were detected by ELISA assay, and Iba-1 (the microglia marker protein) positive cells was measured by immunofluorescence (IF). Western blot and IF were utilized to examine the levels of key molecules in SIRT1/FOXO3a and SIRT1/BRCC3/NLRP3 signaling pathways.

RESULTS

TEAS significantly decreased brain infarcted size and apoptotic neuronal number, and alleviated neurological deficit scores and morphological injury by activating SIRT1. The results of RNA-seq and bioinformatic analysis revealed that oxidative stress and inflammation were the key pathological mechanisms, and TEAS alleviated oxidative injury and inflammatory reactions following ischemic stroke. Then, further investigation indicated that TEAS notably attenuated neuronal apoptosis, neuroinflammation and oxidative stress damage in the hippocampus of rats with MCAO/R surgery. Moreover, TEAS intervention in the MCAO/R model significantly elevated the expressions of SIRT1, FOXO3a, CAT, BRCC3, NLRP3 in the hippocampus. Furthermore, EX527, as the inhibitor of SIRT1, obviously abolished the anti-oxidative stress and anti-neuroinflammatory roles of TEAS, as well as reversed the TEAS-mediated elevation of SIRT1, FOXO3a, CAT and reduction of BRCC3 and NLRP3 mediated by following MCAO/R surgery.

CONCLUSIONS

In summary, these findings clearly suggested that TEAS attenuated brain damage by suppressing apoptosis, oxidative stress and neuroinflammation through modulating SIRT1/FOXO3a and SIRT1/BRCC3/NLRP3 signaling pathways following ischemic stroke, which can be a promising treatment for stroke patients.

Epigallocatechin gallate improves neuronal damage in animal model of ischemic stroke and glutamate-exposed neurons via modulation of hippocalcin expression

Epigallocatechin gallate (EGCG) is a polyphenolic component of green tea that has anti-oxidative and anti-inflammatory effects in neurons. Ischemic stroke is a major neurological disease that causes irreversible brain disorders. It increases the intracellular calcium concentration and induces apoptosis. The regulation of intracellular calcium concentration is important to maintain the function of the nervous system. Hippocalcin is a neuronal calcium sensor protein that controls intracellular calcium concentration. We investigated whether EGCG treatment regulates the expression of hippocalcin in stroke animal model and glutamate-induced neuronal damage. We performed middle cerebral artery occlusion (MCAO) to induce cerebral ischemia. EGCG (50 mg/kg) or phosphate buffered saline was injected into the abdominal cavity just before MCAO surgery. The neurobehavioral tests were performed 24 h after MCAO surgery and cerebral cortex tissue was collected. MCAO damage induced severe neurobehavioral disorders, increased infarct volume, and decreased the expression of hippocalcin in the cerebral cortex. However, EGCG treatment improved these deficits and alleviated the decrease in hippocalcin expression in cerebral cortex. In addition, EGCG dose-dependently alleviated neuronal cell death and intracellular calcium overload in glutamate-exposed neurons. Glutamate exposure reduced hippocalcin expression, decreased Bcl-2 expression, and increased Bax expression. However, EGCG treatment mitigated these changes caused by glutamate toxicity. EGCG also attenuated the increase in caspase-3 and cleaved caspase-3 expressions caused by glutamate exposure. The effect of EGCG was more pronounced in non-transfected cells than in hippocalcin siRNA-transfected cells. These findings demonstrate that EGCG protects neurons against glutamate toxicity through the regulation of Bcl-2 family proteins and caspase-3. It is known that hippocalcin exerts anti-apoptotic effect through the modulation of apoptotic pathway. Thus, we can suggest evidence that EGCG has a neuroprotective effect by regulating hippocalcin expression in ischemic brain damage and glutamate-exposed cells.

Oxyberberine protects middle cerebral artery occlusion triggered cerebral injury through TLR4/NLRP3 pathway in rats

Cerebral ischemia is a life-threatening health concern that leads to severe neurological complications and fatalities worldwide. Although timely intervention with clot-removing agents curtails serious post-stroke neurological dysfunctions, no effective neuroprotective intervention is available for addressing post-recanalization neuroinflammation. Herein, for the first time we studied the effect of oxyberberine (OBB), a derivative of berberine, on transient middle cerebral artery occlusion (MCAO)-generated neurological consequences in Sprague-Dawley rats. The MCAO-operated rats exhibited significant somatosensory and sensorimotor dysfunctions in adhesive removal, foot fault, paw whisker, and rotarod assays at 1 and 3 days post-surgery. These MCAO-generated neurological deficits were prevented in OBB-treated (50 and 100 mg/kg) rats, and also coincided with a smaller infarct area (in 2,3,5-triphenyl tetrazolium chloride staining) and decreased neuronal death (in cresyl violet staining) in the ipsilateral hemisphere of these animals. The immunostaining of neuronal nuclear protein (NeuN) and glial-fibrillary acidic protein (GFAP) also echoes the neuroprotective nature of OBB. The increased expression of neuroinflammatory and blood-brain barrier tight junction proteins like toll-like receptor 4 (TLR4), TRAF-6, nuclear factor kappa B (NF-κB), pNF-κB, nNOS, ASC, and IKBα in the ipsilateral part of MCAO-operated rats were restored to normal following OBB treatment. We also observed the decline in plasma levels/mRNA transcription of TNF-α, IL-1β, NLRP3, IL-6, and matrix metalloproteinase-9 and increased expression of occludin and claudin in OBB-treated rats. These outcomes imply that OBB may prevent the MCAO-induced neurological consequences and neuroinflammation by interfering with TLR4 and NLRP3 signaling in rats.

Dl-3-n-Butylphthalide Alleviates Secondary Brain Damage and Improves Working Memory After Stroke in Cynomolgus Monkeys

BACKGROUND

Remote secondary neurodegeneration is associated with poststroke cognitive impairment (PSCI). Dl-3-n-butylphthalide (NBP) improves PSCI clinically. However, whether it ameliorates PSCI by alleviating secondary neurodegeneration remains uncertain. Nonhuman primates provide more relevant models than rodents for human stroke and PSCI. This study investigated the effects of NBP on PSCI and secondary neurodegeneration in cynomolgus monkeys after permanent left middle cerebral artery occlusion (MCAO).

METHODS

Thirteen adult male cynomolgus monkeys were randomly assigned to sham (n=4), MCAO+placebo (n=5), and MCAO+NBP groups (n=4). The MCAO+placebo and MCAO+NBP groups received saline and NBP injections intravenously, respectively, starting at 6-hour postsurgery for 2 weeks, followed by soybean oil and NBP orally, respectively, for 10 weeks after MCAO. Infarct size was assessed at week 4 by magnetic resonance imaging. Working memory and executive function were evaluated dynamically using the delayed response task and object retrieval detour task, respectively. Neuron loss, glia proliferation, and neuroinflammation in the ipsilateral dorsal lateral prefrontal cortex, thalamus, and hippocampus were analyzed by immunostaining 12 weeks after MCAO.

RESULTS

Infarcts were located in the left middle cerebral artery region, apart from the ipsilateral dorsal lateral prefrontal cortex, thalamus, or hippocampus, with no significant difference between the MCAO+placebo and MCAO+NBP group. Higher success in delayed response task was achieved at weeks 4, 8, and 12 after NBP compared with placebo treatments (P<0.05), but not in the object retrieval detour task (all P>0.05). More neurons and less microglia, astrocytes, CD68-positive microglia, tumor necrosis factor-α, and inducible NO synthase were observed in the ipsilateral dorsal lateral prefrontal cortex and thalamus after 12 weeks of NBP treatment (P<0.05), but not in the hippocampus (P>0.05).

CONCLUSIONS

Our findings indicate that NBP improves working memory by alleviating remote secondary neurodegeneration and neuroinflammation in the ipsilateral dorsal lateral prefrontal cortex and thalamus after MCAO in cynomolgus monkeys.

Impact of the pandemic and concomitant COVID-19 on the management and outcomes of middle cerebral artery strokes: a nationwide registry-based study

OBJECTIVES

To investigate the impact of the COVID-19 pandemic as well as concomitant COVID-19 itself on stroke care, focusing on middle cerebral artery (MCA) territory infarctions.

DESIGN

Registry-based study.

SETTING

We used the National Inpatient Sample (NIS) database, which covers a wide range of hospitals within the USA.

PARTICIPANTS

The NIS was queried for patients with MCA strokes between 2016 and 2020. In total, 35 231 patients were included.

OUTCOME MEASURES

Outcome measures were postprocedural complications, length of stays (LOSs), in-hospital mortality and non-routine discharge. Propensity score matching using all available baseline variables was performed to reduce confounders when comparing patients with and without concomitant COVID-19.

RESULTS

Mechanical thrombectomy (MT) was performed in 48.4%, intravenous thrombolysis (IVT) in 38.2%, and both MT and IVT (MT+IVT) in 13.4% of patients. A gradual increase in the use of MT and an opposite decrease in the use of IVT (p<0.001) was detected during the study period. Overall, 25.0% of all patients were admitted for MCA strokes during the pandemic period (2020), of these 209 (2.4%) were concomitantly diagnosed with COVID-19. Patients with MCA strokes and concomitant COVID-19 were significantly younger (64.9 vs 70.0; p<0.001), had significantly worse NIH Stroke Severity scores, and worse outcomes in terms of LOS (12.3 vs 8.2; p<0.001), in-hospital mortality (26.3% vs 9.8%; p<0.001) and non-routine discharge (84.2% vs 76.9%; p=0.013), as compared with those without COVID-19. After matching, only in-hospital mortality rates remained significantly higher in patients with COVID-19 (26.7% vs 8.5%; p<0.001). Additionally, patients with COVID-19 had higher rates of thromboembolic (12.3% vs 7.6%; p=0.035) and respiratory (11.3% vs 6.6%; p=0.029) complications.

CONCLUSIONS

Among patients with MCA stroke, those with concomitant COVID-19 were significantly younger and had higher stroke severity scores. They were more likely to experience thromboembolic and respiratory complications and in-hospital mortality compared with matched controls.

YTHDF2-regulated matrilin-3 mitigates post-reperfusion hemorrhagic transformation in ischemic stroke via the PI3K/AKT pathway

Hemorrhagic transformation can complicate ischemic strokes after recanalization treatment within a time window that requires early intervention. To determine potential therapeutic effects of matrilin-3, rat cerebral ischemia-reperfusion was produced using transient middle cerebral artery occlusion (tMCAO); intracranial hemorrhage and infarct volumes were assayed through hemoglobin determination and 2,3,5-triphenyltetrazoliumchloride (TTC) staining, respectively. Oxygen-glucose deprivation (OGD) modeling of ischemia was performed on C8-D1A cells. Interactions between matrilin-3 and YTH N6-methyladenosine RNA binding protein F2 (YTHDF2) were determined using RNA immunoprecipitation assay and actinomycin D treatment. Reperfusion after tMCAO modeling increased hemorrhage, hemoglobin content, and infarct volumes; these were alleviated by matrilin treatment. Matrilin-3 was expressed at low levels and YTHDF2 was expressed at high levels in ischemic brains. In OGD-induced cells, matrilin-3 was negatively regulated by YTHDF2. Matrilin-3 overexpression downregulated p-PI3K/PI3K, p-AKT/AKT, ZO-1, VE-cadherin and occludin, and upregulated p-JNK/JNK in ischemic rat brains; these effects were reversed by LY294002 (a PI3K inhibitor). YTHDF2 knockdown inactivated the PI3K/AKT pathway, inhibited inflammation and decreased blood-brain barrier-related protein levels in cells; these effects were reversed by matrilin-3 deficiency. These results indicate that YTHDF2-regulated matrilin-3 protected ischemic rats against post-reperfusion hemorrhagic transformation via the PI3K/AKT pathway and that matrilin may have therapeutic potential in ischemic stroke.

Polygalasaponin F ameliorates middle cerebral artery occlusion-induced focal ischemia / reperfusion injury in rats through inhibiting TXNIP/NLRP3 signaling pathway

BACKGROUND

Polygalasaponin F (PGSF), an oleanane triterpenoid saponin extracted from Polygala japonica, has been demonstrated with neuroprotective effect. However, the therapeutic effects and mechanisms of PGSF on focal ischemia remain unknown; METHODS: In this study, male Sprague Dawley (SD) rats aged 6-8 weeks were initially selected to establish a rat model of middle cerebral artery occlusion (MCAO) to evaluate the therapeutic effect of PGSF intervention and to investigate the impact of PGSF on the thioredoxin-interacting protein/NOD-, LRR-, and pyrin domain-containing protein 3 (TXNIP/NLRP3) inflammatory pathway. Secondly, brain neuron cells were isolated, and the cells received oxygen-glucose deprivation/reoxygenation (OGD/R) culture to establish the cell injury model in vitro. The mechanism of PGSF on the TXNIP/NLRP3 pathway was further validated; RESULTS: Our results showed that PGSF treatment reduced neurological scores, brain tissue water content and infarct volume and ameliorated the pathological changes in cerebral cortex in MCAO-induced focal ischemia rats. The TNF-α, IL-1β and IL-6 levels decreased in MCAO-induced focal ischemia rats after PGSF treatment. Moreover, PGSF down-regulated the protein expressions of TXNIP, NLRP3, ASC, cleaved caspase-1, IL-1β, and IL-18 in MCAO-induced focal ischemia rats. Meanwhile, PGSF treatment inhibited apoptosis, and reduced the levels of ROS, inflammatory cytokine and TXNIP/NLRP3 pathway-related proteins (TXNIP, NLRP3, ASC, cleaved caspase-1, IL-1β, and IL-18) in OGD/R-induced neuronal injury cells. Finally, PGSF treatment also disrupted the interaction between NLRP3 and TXNIP in vitro; CONCLUSIONS: Our study demonstrated the therapeutic effects of PGSF on MCAO-induced focal ischemia rats. Moreover, the neuroprotective mechanism of PGSF on focal ischemia was associated with the inhibition of TXNIP/NLRP3 signaling pathway.

Suppression of cerebral ischemia injury induced blood brain barrier breakdown by dexmedetomidine via promoting CCN1

BACKGROUND

Blood-brain barrier (BBB) could aggravate cerebral ischemia injury. Dexmedetomidine (Dex) has been believed to play a protective role in cerebral ischemia injury-induced BBB injury.

METHODS

Middle cerebral artery occlusion (MCAO) and oxygen-glucose deprivation (OGD) models were established to simulate cerebral ischemia injury. Animal experiments included 4 groups, Sham, MCAO, MCAO+Dex, MCAO+Dex+sh-CCN1. Generally applicable gene set enrichment analysis was performed to analyze gene expression difference. Total collagen content and Evans blue staining were performed to measure infarct ratio and BBB breakdown, respectively. The cell apoptosis, mRNA and protein expression were measured through flow cytometry, PCR, and western blotting, respectively. The levels of IL-1β, TNF-α, and IL-6 in serum were measured with commercial ELISA kits.

RESULTS

Dex greatly promoted the expression level of CCN1. Dex suppressed cerebral ischemia injury, increased tight junction protein expression, improved the memory ability and neurological function of MCAO rats through targeting CCN1. The significant increase of inflammatory factors in the serum of MCAO rats were suppressed by Dex. Dex suppressed OGD induced increase of HRP permeability and promoting tight junction protein expression in vitro through regulating CCN1. The neurological function evaluation was performed with Neurological Severity Score (NSS) and Longa Score Scale.

CONCLUSIONS

Dex could remarkably alleviate cerebral ischemia injury by inhibiting BBB breakdown, inflammatory response, and promoting neurological function and tight junction protein expression via up-regulating CCN1. This study might provide a novel therapeutic target for the prevention and treatment of cerebral ischemia injury-induced BBB.

GPR55 Inactivation Diminishes Splenic Responses and Improves Neurological Outcomes in the Mouse Ischemia/Reperfusion Stroke Model

Although strokes are frequent and severe, treatment options are scarce. Plasminogen activators, the only FDA-approved agents for clot treatment (tissue plasminogen activators (tPAs)), are used in a limited patient group. Moreover, there are few approaches for handling the brain's inflammatory reactions to a stroke. The orphan G protein-coupled receptor 55 (GPR55)'s connection to inflammatory processes has been recently reported; however, its role in stroke remains to be discovered. Post-stroke neuroinflammation involves the central nervous system (CNS)'s resident microglia activation and the infiltration of leukocytes from circulation into the brain. Additionally, splenic responses have been shown to be detrimental to stroke recovery. While lymphocytes enter the brain in small numbers, they regularly emerge as a very influential leukocyte subset that causes secondary inflammatory cerebral damage. However, an understanding of how this limited lymphocyte presence profoundly impacts stroke outcomes remains largely unclear. In this study, a mouse model for transient middle cerebral artery occlusion (tMCAO) was used to mimic ischemia followed by a reperfusion (IS/R) stroke. GPR55 inactivation, with a potent GPR55-specific antagonist, ML-193, starting 6 h after tMCAO or the absence of the GPR55 in mice (GPR55 knock out (GPR55ko)) resulted in a reduced infarction volume, improved neurological outcomes, and decreased splenic responses. The inhibition of GPR55 with ML-193 diminished CD4+T-cell spleen egress and attenuated CD4+T-cell brain infiltration. Additionally, ML-193 treatment resulted in an augmented number of regulatory T cells (Tregs) in the brain post-tMCAO. Our report offers documentation and the functional evaluation of GPR55 in the brain-spleen axis and lays the foundation for refining therapeutics for patients after ischemic attacks.

Gypenoside Pretreatment Alleviates the Cerebral Ischemia Injury via Inhibiting the Microglia-Mediated Neuroinflammation

Neuroinflammation is closely related to prognosis in ischemic stroke. Microglia are the main immune cells in the nervous system. Under physiological conditions, microglia participate in clearance of dead cells, synapse pruning and regulation of neuronal circuits to maintain the overall health of the nervous system. Once ischemic stroke occurs, microglia function in the occurrence and progression of neuroinflammation. Therefore, the regulation of microglia-mediated neuroinflammation is a potential therapeutic strategy for ischemic stroke. The anti-inflammatory activity of gypenosides (GPs) has been confirmed to be related to the activity of microglia in other neurological diseases. However, the role of GPs in neuroinflammation after ischemic stroke has not been studied. In this study, we investigated whether GPs could reduce neuroinflammation by regulating microglia and the underlying mechanism through qRT-PCR and western blot. Results showed that GPs pretreatment mitigated blood-brain barrier (BBB) damage in the mice subjected to middle cerebral artery occlusion (MCAO) and improved motor function. According to the results of immunofluorescence staining, GPs pretreatment alleviated neuroinflammation in MCAO mice by reducing the number of microglia and promoting their phenotypic transformation from M1 to M2. Furthermore, GPs pretreatment reduced the number of astrocytes in the penumbra and inhibited their polarization into the A1 type. We applied oxygen and glucose deprivation (OGD) on BV2 cells to mimic ischemic conditions in vitro and found similar effect as that in vivo. At the molecular level, the STAT-3/HIF1-α and TLR-4/NF-κB/HIF1-α pathways were involved in the anti-inflammatory effects of GPs in vitro and in vivo. Overall, this research indicates that GPs are potential therapeutic agents for ischemic stroke and has important reference significance to further explore the possibility of GPs application in ischemic stroke.

Combined Technique for Internal Carotid Artery Terminus or Middle Cerebral Artery Occlusions in the ASTER2 Trial

BACKGROUND

The aim of this study was to report the results of a subgroup analysis of the ASTER2 trial (Effect of Thrombectomy With Combined Contact Aspiration and Stent Retriever vs Stent Retriever Alone on Revascularization in Patients With Acute Ischemic Stroke and Large Vessel Occlusion) comparing the safety and efficacy of the combined technique (CoT) and stent retriever as a first-line approach in internal carotid artery (ICA) terminus±M1-middle cerebral artery (M1-MCA) and isolated M1-MCA occlusions.

METHODS

Patients enrolled in the ASTER2 trial with ICA terminus±M1-MCA and isolated M1-MCA occlusions were included in this subgroup analysis. The effect of first-line CoT versus stent retriever according to the occlusion site was assessed on angiographic (first-pass effect, expanded Treatment in Cerebral Infarction score ≥2b50, and expanded Treatment in Cerebral Infarction score ≥2c grades at the end of the first-line strategy and at the end of the procedure) and clinicoradiological outcomes (24-hour National Institutes of Health Stroke Scale, ECASS-III [European Cooperative Acute Stroke Study] grades, and 3-month modified Rankin Scale).

RESULTS

Three hundred sixty-two patients were included in the postsubgroup analysis according to the occlusion site: 299 were treated for isolated M1-MCA occlusion (150 with first-line CoT) and 63 were treated for ICA terminus±M1-MCA occlusion (30 with first-line CoT). Expanded Treatment in Cerebral Infarction score ≥2b50 (odds ratio, 11.83 [95% CI, 2.32-60.12]) and expanded Treatment in Cerebral Infarction score ≥2c (odds ratio, 4.09 [95% CI, 1.39-11.94]) were significantly higher in first-line CoT compared with first-line stent retriever in patients with ICA terminus±M1-MCA occlusion but not in patients with isolated M1-MCA.

CONCLUSIONS

First-line CoT was associated with higher reperfusion grades in patients with ICA terminus±M1-MCA at the end of the procedure.

REGISTRATION

URL: https://www.clinicaltrials.gov; Unique identifier: NCT03290885.

Post-stroke brain can be protected by modulating the lncRNA FosDT

We previously showed that knockdown or deletion of Fos downstream transcript (FosDT; a stroke-induced brain-specific long noncoding RNA) is neuroprotective. We presently tested the therapeutic potential of FosDT siRNA in rodents subjected to transient middle cerebral artery occlusion (MCAO) using the Stroke Treatment Academic Industry Roundtable criteria, including sex, age, species, and comorbidity. FosDT siRNA (IV) given at 30 min of reperfusion significantly improved motor function recovery (rotarod test, beam walk test, and adhesive removal test) and reduced infarct size in adult and aged spontaneously hypertensive rats of both sexes. FosDT siRNA administered in a delayed fashion (3.5 h of reperfusion following 1 h transient MCAO) also significantly improved motor function recovery and decreased infarct volume. Furthermore, FosDT siRNA enhanced post-stroke functional recovery in normal and diabetic mice. Mechanistically, FosDT triggered post-ischemic neuronal damage via the transcription factor REST as REST siRNA mitigated the enhanced functional outcome in FosDT-/- rats. Additionally, NF-κB regulated FosDT expression as NF-κB inhibitor BAY 11-7082 significantly decreased post-ischemic FosDT induction. Thus, FosDT is a promising target with a favorable therapeutic window to mitigate secondary brain damage and facilitate recovery after stroke regardless of sex, age, species, and comorbidity.

ATG5 Knockdown Attenuates Ischemia‒Reperfusion Injury by Reducing Excessive Autophagy-Induced Ferroptosis

Autophagy has been described to be both protective and pathogenic in cerebral ischemia/reperfusion (I/R) injury. The underlying association between autophagy and ferroptosis in ischemic stroke has not yet been clearly investigated. The purpose of this study was to explore the role of autophagy-related gene 5 (ATG5) in experimental ischemic stroke. After injection of ATG5 shRNA lentivirus, mice underwent surgery for transient middle cerebral artery occlusion (MCAO)-induced focal cerebral ischemia. The infarct volume, neurological function, apoptosis, reactive oxygen species (ROS), autophagy, and ferroptosis levels were evaluated. After MCAO, ATG5-knockdown mice had a smaller infarct size and fewer neurological deficits than wild-type mice. The levels of apoptosis and ROS in ischemic mouse brains were alleviated through ATG5 knockdown. The expression of LC3 I/II was reduced through ATG5 knockdown after MCAO. Additionally, the expression of beclin1 and LC3 II was increased after I/R, but the increase was counteracted by preconditioning with ATG5 knockdown. After ischemic stroke, the levels of Fe2+ and malondialdehyde (MDA) were increased, but they were reduced by ATG5 knockdown. Similarly, the expression of glutathione peroxidase 4 (GPX4) and glutathione (GSH) was decreased by I/R but elevated by ATG5 knockdown. The present study shows that ATG5 knockdown attenuates autophagy-induced ferroptosis, which may offer a novel potential approach for ischemic stroke treatment.

TGN-020 Alleviate Inflammation and Apoptosis After Cerebral Ischemia-Reperfusion Injury in Mice Through Glymphatic and ERK1/2 Signaling Pathway

Post-stroke acute inhibition of aquaporin 4 (AQP4) is known to exacerbate inflammation and apoptosis, yet the underlying mechanisms are not fully understood. The objective of this study was to investigate the specific mechanism of inflammation and apoptosis following cerebral ischemia-reperfusion (I/R) injury using the AQP4-specific inhibitor, N-(1,3,4-thiadiazol-2-yl) pyridine-3-carboxamide dihydrochloride (TGN-020). Ischemic stroke was induced in mice using the middle cerebral artery occlusion (MCAO) model. The C57/BL6 mice were randomly divided into three groups as follows: sham operation, I/R 48 h, and TGN-020 + I/R 48 h treatment. All mice were subjected to a series of procedures. These procedures encompassed 2,3,5-triphenyltetrazolium chloride (TTC) staining, neurological scoring, fluorescence tracing, western blotting, immunofluorescence staining, and RNA sequencing (RNA-seq). The glymphatic function in the cortex surrounding cerebral infarction was determined using tracer, glial fibrillary acid protein (GFAP), AQP4 co-staining, and beta-amyloid precursor protein (APP) staining; differential genes were detected using RNA-seq. The influence of TGN-020 on the extracellular signal-regulated kinase 1/2 (ERK) 1/2 pathway was confirmed using the ERK1/2 pathway agonists Ro 67-7467. Additionally, we examined the expression of inflammation associated with microglia and astrocytes after TGN-020 and Ro 67-7467 treatment. Compared with I/R group, TGN-020 alleviated glymphatic dysfunction by inhibiting astrocyte proliferation and reducing tracer accumulation in the peri-infarct area. RNA-seq showed that the differentially expressed genes were mainly involved in the activation of astrocytes and microglia and in the ERK1/2 pathway. Western blot and immunofluorescence further verified the expression of associated inflammation. The inflammation and cell apoptosis induced by I/R are mitigated by TGN-020. This mitigation occurs through the improvement of glymphatic function and the inhibition of the ERK1/2 pathway.

SRGN amplifies microglia-mediated neuroinflammation and exacerbates ischemic brain injury

BACKGROUND

Microglia is the major contributor of post-stroke neuroinflammation cascade and the crucial cellular target for the treatment of ischemic stroke. Currently, the endogenous mechanism underlying microglial activation following ischemic stroke remains elusive. Serglycin (SRGN) is a proteoglycan expressed in immune cells. Up to now, the role of SRGN on microglial activation and ischemic stroke is largely unexplored.

METHODS

Srgn knockout (KO), Cd44-KO and wild-type (WT) mice were subjected to middle cerebral artery occlusion (MCAO) to mimic ischemic stroke. Exogenous SRGN supplementation was achieved by stereotactic injection of recombinant mouse SRGN (rSRGN). Cerebral infarction was measured by 2,3,5-triphenyltetrazolium chloride (TTC) staining. Neurological functions were evaluated by the modified neurological severity score (mNSS) and grip strength. Microglial activation was detected by Iba1 immunostaining, morphological analysis and cytokines' production. Neuronal death was examined by MAP2 immunostaining and FJB staining.

RESULTS

The expression of SRGN and its receptor CD44 was significantly elevated in the ischemic mouse brains, especially in microglia. In addition, lipopolysaccharide (LPS) induced SRGN upregulation in microglia in vitro. rSRGN worsened ischemic brain injury in mice and amplified post-stroke neuroinflammation, while gene knockout of Srgn exerted reverse impacts. rSRGN promoted microglial proinflammatory activation both in vivo and in vitro, whereas Srgn-deficiency alleviated microglia-mediated inflammatory response. Moreover, the genetic deletion of Cd44 partially rescued rSRGN-induced excessed neuroinflammation and ischemic brain injury in mice. Mechanistically, SRGN boosted the activation of NF-κB signal, and increased glycolysis in microglia.

CONCLUSION

SRGN acts as a novel therapeutic target in microglia-boosted proinflammatory response following ischemic stroke.

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-1β 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.

Chicago sky blue 6B exerts neuroprotective and anti-inflammatory effects on focal cerebral ischemia

Brain ischemia is one of the leading causes of death and long-term disability worldwide. Cessation of the blood supply to the brain directly stimulates many pathological events, including glutamate overload and neuroinflammation. Glial cell activation occurs shortly after ischemia onset, resulting in the release of proinflammatory cytokines and exacerbation of the detrimental effects of neuroinflammation. Proinflammatory signals influence the infiltration of a wide range of immune cells, including neutrophils, T cells and monocytes/macrophages. In this study, we aimed to verify the potential anti-inflammatory effect of Chicago Sky Blue 6B (CSB6B) in a rat model of focal cerebral ischemia (90-minute middle cerebral artery occlusion). CSB6B was administered 2 h before (pretreatment) or 1.5 h after reperfusion onset (posttreatment). A model of ischemic preconditioning was used as the comparator to pretreatment with CSB6B. The results of indicated that posttreatment with CSB6B had profound anti-inflammatory effects that were associated with reduced neurological deficits and a decreased infarct volume. At 24 h, 3 days and 7 days after brain ischemia, CSB6B administration reduced the protein levels of proinflammatory cytokines, such as Il1β, Il6, Il18 and TNFα, in the cerebral cortex and the dorsal striatum. Treatment with CSB6B also limited the scope of microglia and astrocyte activation and the infiltration of immune cells. Taken together, this study shows that compounds such as CSB6B might be promising pharmacological tools; however, further studies on the improvements in the drug-like properties of these compounds must be undertaken.

Rat Model of Middle Cerebral Artery Occlusion

Stroke is the third-leading cause of death and the leading cause of acquired adult disability worldwide. Several ischemic stroke models are currently available. However, mimicking focal cerebral ischemia (FCI) is the most common. The formation of an embolic or thrombotic occlusion at or near the middle cerebral artery causes most events in FCI. The current protocol closely mimics the etiology of human stroke and ensures that the results obtained are highly relevant. The method described in this protocol yields reproducible results. The success of this model in ischemic research can be examined through the utilization of Doppler blood flow imaging equipment.

Role of Lipocalin-2 in N1/N2 Neutrophil Polarization After Stroke

BACKGROUND

Neutrophils and Lipocalin-2 (LCN2) play pivotal roles in cerebral ischemiareperfusion (I/R) injury. However, their contribution is not fully clarified.

OBJECTIVE

This study aimed to explore the role of LCN2 and its association with neutrophil polarization in I/R injury.

METHODS

A mouse model of middle cerebral artery occlusion (MCAO) was used to induce cerebral ischemia. LCN2mAb was administered 1 h and Anti-Ly6G was administered for 3d before MCAO. The role of LCN2 in the polarity transition of neutrophils was explored using an in vitro HL-60 cell model.

RESULTS

LCN2mAb pretreatment had neuroprotective effects in mice. The expression of Ly6G was not significantly different, but the expression of N2 neutrophils was increased. In the in vitro study, LCN2mAb-treated N1-HL-60 cells induced N2-HL-60 polarization.

CONCLUSION

LCN2 may affect the prognosis of ischemic stroke by mediating neutrophil polarization.

Pathogenic role of NAMPT in the perivascular regions after ischemic stroke in mice with type 2 diabetes mellitus

Ischemic stroke in patients with abnormal glucose tolerance results in poor outcomes. Nicotinamide phosphoribosyltransferase (NAMPT), an adipocytokine, exerts neuroprotective effects. However, the pathophysiological role of NAMPT after ischemic stroke with diabetes and the relationship of NAMPT with cerebrovascular lesions are unclear. The purpose of this study was to clarify the pathophysiological role of NAMPT in cerebral ischemia with diabetes, using db/db mice as a type 2 diabetes animal model. The number of degenerating neurons increased after middle cerebral artery occlusion and reperfusion (MCAO/R) in db/db mice compared with the degenerating neurons in db/+ mice. Extracellular NAMPT (eNAMPT) levels, especially monomeric eNAMPT, increased significantly in db/db MCAO/R mice but not db/+ mice in isolated brain microvessels. The increased eNAMPT levels were associated with increased expression of inflammatory cytokine mRNA. Immunohistochemical analysis demonstrated that NAMPT colocalized with GFAP-positive cells after MCAO/R. In addition, both dimeric and monomeric eNAMPT levels increased in the conditioned medium of primary cortical astrocytes under high glucose conditions subsequent oxygen/glucose deprivation. Our findings are the first to demonstrate the ability of increased monomeric eNAMPT to induce inflammatory responses in brain microvessels, which may be located near astrocyte foot processes.

HSP90β regulates EAAT2 expression and participates in ischemia‑reperfusion injury in rats

Cerebrovascular diseases (CVDs) have become a global public health problem and ischemia‑reperfusion injury, the major cause of neurological impairment exacerbation, is closely related to excitotoxicity. The present study aimed to investigate the effects of changes in heat shock protein (HSP)90β expression and verify whether HSP90β regulates EAAT2 expression in a cerebral ischemia‑reperfusion injury model. Healthy adult Sprague‑Dawley (SD) male rats were used to establish a control group, sham‑operated group, middle cerebral artery occlusion (MCAO) group, empty virus group and lentivirus group. A model of cerebral ischemia‑reperfusion was established using the MCAO method. Lentivirus construction and injection were used to interfere with the expression of HSP90β. The modified neurological severity score was used to assess neurological deficits. Triphenyltetrazolium chloride staining was used to detect infarct areas. Immunofluorescence was used to detect HSP90β expression localization and the expression levels of HSP90β and EAAT2 were determined using western blotting and reverse transcription‑quantitative PCR. An MCAO model was successfully established and it was found that HSP90β, but not HSP90α, was upregulated after MCAO. HSP90β expression coincided with astrocyte markers in the ischemic penumbra area, while no expression was observed in microglia. Inhibition of HSP90β expression improved neurological deficits and alleviated brain injury by increasing EAAT2 expression. These results suggested that HSP90β is involved in the process of cerebral ischemia‑reperfusion injury in rats and that inhibition of HSP90β expression increases EAAT2 levels, conferring a neuroprotective effect in MCAO model rats.

P-Glycoprotein Exacerbates Brain Injury Following Experimental Cerebral Ischemia by Promoting Proinflammatory Microglia Activation

Microglia are activated following cerebral ischemic insult. P-glycoprotein (P-gp) is an efflux transporter on microvascular endothelial cells and upregulated after cerebral ischemia. This study evaluated the effects and possible mechanisms of P-gp on microglial polarization/activation in mice after ischemic stroke. P-gp-specific siRNA and adeno-associated virus (p-AAV) were used to silence and overexpress P-gp, respectively. Middle cerebral artery occlusion/reperfusion (MCAO/R) and oxygen-glucose deprivation/reoxygenation (OGD/R) were performed in mice and cerebral microvascular endothelial cells (bEnd.3) in vitro, respectively. OGD/R-injured bEnd.3 cells were cocultured with mouse microglial cells (BV2) in Transwell. Influences on acute ischemic stroke outcome, the expression of inflammatory cytokines, and chemokines and chemokines receptors, microglial polarization, glucocorticoid receptor (GR) nuclear translocation, and GR-mediated mRNA decay (GMD) activation were evaluated via reverse transcription real-time polymerase chain reaction, western blot, or immunofluorescence. Silencing P-gp markedly alleviated experimental ischemia injury as indicated by reduced cerebral infarct size, improved neurological deficits, and reduced the expression of interleukin-6 (IL-6) and IL-12 expression. Silencing P-gp also mitigated proinflammatory microglial polarization and the expression of C-C motif chemokine ligand 2 (CCL2) and its receptor CCR2 expression, whereas promoted anti-inflammatory microglia polarization. Additionally, P-gp silencing promoted GR nuclear translocation and the expression of GMD relative proteins in endothelial cells. Conversely, overexpressing P-gp via p-AAV transfection offset all these effects. Furthermore, silencing endothelial GR counteracted all effects mediated by silencing or overexpressing P-gp. Elevated P-gp expression aggravated inflammatory response and brain damage after ischemic stroke by augmenting proinflammatory microglial polarization in association with increased endothelial CCL2 release due to GMD inhibition by P-gp.

Basal ganglia ischaemic infarction after thrombectomy: cognitive impairment at acute stage

BACKGROUND AND PURPOSE

After successful mechanical thrombectomy for middle cerebral artery occlusion, basal ganglia infarction is commonly detectable. Whilst the functional outcome of these patients is often good, less knowledge is available about the cognitive outcome. The aim of our study was to assess the presence of cognitive impairment within 1 week after thrombectomy.

METHODS

In all, 43 subjects underwent a general cognitive assessment using the Montreal Cognitive Assessment and an extensive battery of tests. Patients were classified as cognitively impaired (CImp) or not (noCImp) according to a Montreal Cognitive Assessment score below 18.

RESULTS

Cognitively impaired and noCImp subjects did not differ either in their National Institutes of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS) at admittance, or in their Fazekas score and Alberta Stroke Program Early Computed Tomography Score. At discharge, CImp subjects showed higher scores than noCImp subjects on NIHSS (p = 0.002) and mRS (p < 0.001). The percentage of pathological performances on each neuropsychological test in the whole sample and in CImp and noCImp patients shows a similar cognitive profile between the groups.

CONCLUSIONS

Some patients who underwent thrombectomy experienced a detectable cognitive impairment that probably led to worse NIHSS and mRS. The neuropsychological profile of such cognitive impairment at the acute stage consists of wide deficits in numerous cognitive domains, suggesting that basal ganglia damage may lead to complex functional impairments.

Recombinant human brain natriuretic peptide attenuates ischemic brain injury in mice by inhibiting oxidative stress and cell apoptosis via activation of PI3K/AKT/Nrf2/HO-1 pathway

Ischemic stroke followed by cerebral artery occlusion is a main cause of chronic disability worldwide. Recombinant human brain natriuretic peptide (rhBNP) has been reported to alleviate sepsis-induced cognitive dysfunction and brain I/R injury. However, the function and molecular mechanisms of rhBNP in ischemic brain injury have not been clarified. For establishment of an animal model of ischemic brain injury, C57BL/6 mice were treated with middle cerebral artery occlusion (MCAO) surgery for 1 h and reperfusion for 24 h. After subcutaneous injection of rhBNP into model mice, neurologic deficits were assessed by evaluating behavior of mice according to Longa scoring system, and TTC staining was utilized to determine the brain infarct size of mice. The levels of oxidative stress markers, superoxide dismutase (SOD), catalase (CAT), glutathione (GSH) and malondialdehyde (MDA), were detected in hippocampal tissues of mice by corresponding kits. Cell apoptosis in hippocampus tissues was examined by TUNEL staining. Protein levels of antioxidant enzymes (HO-1 and NQO1) in cerebral cortex, apoptotic markers (Bax, Bcl-2, and cleaved caspase), and PI3K/AKT pathway-associated factors in hippocampus were tested by western blot analysis. The results revealed that injection of rhBNP decreased neurologic deficit scores, the percent of brain water content, and infarct volume. Additionally, rhBNP downregulated MDA level, upregulated the levels of SOD, CAT, and GSH in hippocampus of mice, and increased protein levels of HO-1 and NQO1 in the cortex. Cell apoptosis in hippocampus tissues of model mice was inhibited by rhBNP which was shown as the reduced TUNEL-positive cells, the decreased Bax, cleaved caspase-3, and cleaved caspase-9 protein levels, and the enhanced Bcl-2 protein level. In addition, rhBNP treatment activated the PI3K/AKT signaling pathway and upregulated the protein levels of HO-1 and NRF2. Overall, rhBNP activates the PI3K/AKT/HO-1/NRF2 pathway to attenuate ischemic brain injury in mice after MCAO by suppression of cell apoptosis and oxidative stress.

G-CSF improved the memory and dendritic morphology impairments in the hippocampal CA1 pyramidal neurons after brain ischemia in the male rats

BACKGROUND

Stroke remains the leading cause of death and disability in the world. A new potential treatment for stroke is the granulocyte colony-stimulating factor (G-CSF), which exerts neuroprotective effects through multiple mechanisms. Memory impairment is the most common cognitive problem after a stroke. The suggested treatment for memory impairments is cognitive rehabilitation, which is often ineffective. The hippocampus plays an important role in memory formation. This project aimed to study the effect of G-CSF on memory and dendritic morphology of hippocampal CA1 pyramidal neurons after middle cerebral artery occlusion (MCAO)in rats.

METHODS

Male Sprague-Dawley rats were divided into three groups: the sham, control (MCAO + Vehicle), and treatment (MCAO + G-CSF) groups. G-CSF (50 µg/kg S.C) was administered at 6, 24, and 48 h after brain ischemia induction. The passive avoidance task to evaluate learning and memory was performed on days 6 and 7 post-ischemia. Seven days after MCAO, the brain was removed and the hippocampal slices were stained with Golgi. After that, the neurons were analyzed for dendritic morphology and maturity.

OUTCOMES

The data showed that stroke was associated with a significant impairment in the acquisition and retention of passive avoidance tasks, while the G-CSF improved learning and memory loss. The dendritic length, arborization, spine density, and mature spines of the hippocampus CA1 neurons were significantly reduced in the control group, and treatment with G-CSF significantly increased these parameters.

CONCLUSION

G-CSF, even with three doses, improved learning and memory deficits, and dendritic morphological changes in the CA1 hippocampal neurons resulted from brain ischemia.

Sertraline Pre-Treatment Attenuates Hemorrhagic Transformation Induced in Rats after Cerebral Ischemia Reperfusion via Down Regulation of Neuronal CD163: Involvement of M1/M2 Polarization Interchange and Inhibiting Autophagy

Cerebral ischemia reperfusion (I/R) is one of the neurovascular diseases which leads to severe brain deterioration. Haemorrhagic transformation (HT) is the main complication of ischemic stroke. It exacerbates by reperfusion, causing a more deleterious effect on the brain and death. The current study explored the protective effect of sertraline (Sert) against cerebral I/R in rats by inhibiting HT, together with the molecular pathways involved in this effect. Forty-eight wister male rats were divided into 4 groups: Sham, Sert + Sham, I/R, and Sert + I/R. The ischemic model was induced by bilateral occlusion of the common carotid artery for 20 min, then reperfusion for 24 h. Sertraline (20 mg/kg, p.o.) was administrated for 14 days before exposure to ischemia. Pre-treatment with Sert led to a significant attenuation of oxidative stress and inflammation. In addition, Sert attenuated phosphorylation of extracellular regulated kinases and nuclear factor kappa-p65 expression, consequently modulating microglial polarisation to M2 phenotype. Moreover, Sert prevented the hemorrhagic transformation of ischemic stroke as indicated by the notable decrease in neuronal expression of CD163, activity of Heme oxygenase-2 and matrix metalloproteinase-2 and 9 levels. In the same context, Sert decreased levels of autophagy and apoptotic markers. Furthermore, histological examination, Toluidine blue, and Prussian blue stain aligned with the results. In conclusion, Sert protected against cerebral I/R damage by attenuating oxidative stress, inflammation, autophagy, and apoptotic process. It is worth mentioning that our study was the first to show that Sert inhibited hemorrhagic transformation. The protective effect of sertraline against injury induced by cerebral ischemia reperfusion via inhibiting Hemorrhagic transformation.

Astragaloside IV promotes angiogenesis by targeting SIRT7/VEGFA signaling pathway to improve brain injury after cerebral infarction in rats

Cerebral infarction (CI) has become one of the leading causes of death and acquired disability worldwide. Astragaloside IV (AST IV), one of the basic components of Astragalus membranaceus, has a protective effect on CI. However, the underlying mechanism has not been conclusively elucidated. Therefore, this study aims to explore the underlying mechanism of AST IV improving brain injury after CI. Middle cerebral artery occlusion (MCAO) and oxygen-glucose deprivation/reoxygenation (OGD/R) were used to simulate cerebral infarction injury in SD rats and HUVECs cells. Neurologic score, Evans blue, TTC and HE staining were used to observe brain injury in rats. Cell viability and migration were measured in vitro. Angiogenesis was detected by immunofluorescence and tube formation assay, and cell cycle was detected by flow cytometry. Western blot was used to find the expression of related proteins. Molecular docking, virtual mutation, site-directed mutagenesis, MST, and lentivirus silencing were used for target validation. The results showed that AST IV alleviated neurological impairment and promoted angiogenesis after CI. Moreover, AST IV greatly increased the transcription levels of SIRT6 and SIRT7, but had no effect on SIRT1-SIRT5, and promoted cell viability, migration, angiogenesis and S phase ratio in OGD/R-induced HUVECs. Furthermore, AST IV up-regulated the protein expressions of CDK4, cyclin D1, VEGFA and VEGF2R. Interestingly, AST IV not only bound to SIRT7, but also increased the expression of SIRT7. Silencing SIRT7 by lentivirus neutralizes the positive effects of AST IV. Taken together, the present study revealed that AST IV may improve brain tissue damage after CI by targeting SIRT7/VEGFA signaling pathway to promote angiogenesis.

Brain and serum metabolomic studies reveal therapeutic effects of san hua decoction in rats with ischemic stroke

San Hua Decoction (SHD) is a traditional four-herbal formula that has long been used to treat stroke. Our study used a traditional pharmacodynamic approach combined with systematic and untargeted metabolomics analyses to further investigate the therapeutic effects and potential mechanisms of SHD on ischemic stroke (IS). Male Sprague-Dawley rats were randomly divided into control, sham-operated, middle cerebral artery occlusion reperfusion (MCAO/R) model and SHD groups. The SHD group was provided with SHD (7.2 g/kg, i.g.) and the other three groups were provided with equal amounts of purified water once a day in the morning for 10 consecutive days. Our results showed that cerebral infarct volumes were reduced in the SHD group compared with the model group. Besides, SHD enhanced the activity of SOD and decreased MDA level in MCAO/R rats. Meanwhile, SHD could ameliorate pathological abnormalities by reducing neuronal damage, improving the structure of damaged neurons and reducing inflammatory cell infiltration. Metabolomic analysis of brain and serum samples with GC-MS techniques revealed 55 differential metabolites between the sham and model groups. Among them, the levels of 12 metabolites were restored after treatment with SHD. Metabolic pathway analysis showed that SHD improved the levels of 12 metabolites related to amino acid metabolism and carbohydrate metabolism, 9 of which were significantly associated with disease. SHD attenuated brain inflammation after ischemia-reperfusion. The mechanisms underlying the therapeutic effects of SHD in MCAO/R rats are related to amino acid and carbohydrate metabolism.

Homer1 Protects against Retinal Ganglion Cell Pyroptosis by Inhibiting Endoplasmic Reticulum Stress-Associated TXNIP/NLRP3 Inflammasome Activation after Middle Cerebral Artery Occlusion-Induced Retinal Ischemia

Retinal ischemia, after cerebral ischemia, is an easily overlooked pathophysiological problem in which inflammation is considered to play an important role. Pyroptosis is a kind of cell death pattern accompanied by inflammation. Homer scaffold protein 1 (Homer1) has anti-inflammation properties and protects against ischemic injury. However, little is known about pyroptosis following middle cerebral artery occlusion (MCAO)-induced retinal ischemia and the regulatory mechanisms involved by Homer1 for the development of pyroptosis. In the present study, retinal ischemic injury was induced in mice by permanent MCAO in vivo, and retinal ganglion cells (RGCs) were subjected to Oxygen and Glucose Deprivation (OGD) to establish an in vitro model. It was shown that TXNIP/NLRP3-mediated pyroptosis was located predominantly in RGCs, which gradually increased after retinal ischemia and peaked at 24 h after retinal ischemia. Interestingly, the RGCs pyroptosis occurred not only in the cell body but also in the axon. Notably, the occurrence of pyroptosis coincided with the change of Homer1 expression in the retina after retinal ischemia and Homer1 also co-localized with RGCs. It was demonstrated that overexpression of Homer1 not only alleviated RGCs pyroptosis and inhibited the release of pro-inflammatory factors but also led to the increase in phosphorylation of AMPK, inhibition of ER stress, and preservation of visual function after retinal ischemia. In conclusion, it was suggested that Homer1 may protect against MCAO-induced retinal ischemia and RGCs pyroptosis by inhibiting endoplasmic reticulum stress-associated TXNIP/NLRP3 inflammasome activation after MCAO-induced retinal ischemia.