Multiaspect layered double hydroxide nanohybrid counteracts pathophysiological cascade for ischemic stroke intervention.

Microglia-mediated neuroinflammation plays an important role in focal ischemic stroke, a disorder with no effective therapeutic agents. Since microglial polarization to the M2 phenotype and reduction of oxidative stress are mediated through AMP-activated protein kinase (AMPK) and nuclear factor erythroid 2-related factor 2 (Nrf2) activation, we assessed the dual therapeutic effect of AMPK and Nrf2 activation by a novel neuroprotectant HP-1c in the treatment of ischemic stroke. We developed a novel class of hybrids (HP-1a-HP-1f) of telmisartan and 2-(1-hydroxypentyl)-benzoate (HPBA) as a ring-opening derivative of NBP. The most promising hybrid, HP-1c, exhibited more potent anti-inflammatory and neuroprotective effects in vitro and reduced brain infarct volume and improved neurological deficits in a rat model of transient focal cerebral ischemia when compared with telmisartan alone, NBP alone, or a combination of telmisartan and NBP. HP-1c had a therapeutic window of up to 24 h, ameliorated ischemic cerebral injury in permanent focal cerebral ischemia, and improved motor function. The beneficial effects of HP-1c in ischemic stroke were associated with microglial polarization to the M2 phenotype and reduced oxidative stress. HP-1c also shifted the M1/M2 polarization in a mouse neuroinflammatory model. The anti-inflammatory and anti-oxidative effects of HP-1c were associated with AMPK-Nrf2 pathway activation for neuroprotection. We showed that HP-1c penetrates the brain, has a plasma half-life of around 3.93 h, and has no toxicity in mice. Innovation and Conclusion: Our study results suggest that HP-1c, with dual AMPK- and Nrf2-activating properties, may have potential in further studies as a novel therapy for ischemic stroke. Antioxid. Redox Signal. 28, 141-163.

What can be more frustrating for physicians (and, of course, for their patients) than deterioration during treatment? Expectations are high that patients will get better when they come to the hospital, not get worse. Unfortunately, worsening is a common occurrence in patients with brain ischemia despite present treatment. In this issue of Stroke , Steinke and Ley show that, among their stroke patients, worsening of motor function, a very important component of disability, was most common among those who had lacunar strokes.1 The term worsening , as presently used, is arbitrary in that it depends on an extremely variable starting time—entry into medical care. If an individual who becomes considerably more hemiplegic 4 hours after the first symptom of weakness and then stabilizes enters a hospital at hour 2, he or she is classified as worsening. If, instead, the patient enters the hospital at hour 5, he or she would not be classified as worsening. Present designation of worsening then depends on when the clock starts running. I avoid terms based on worsening such as “stroke-in-evolution” and “progressing stroke,” since they depend on a shifting start time. Ideally, physicians should attempt to alter a declining course of illness graph that begins at the time of symptom onset. Worsening during the first few hours often has quite different explanations than worsening during hours 12 to 48. Unfortunately, it is often difficult to quantify deficits present before the patient is seen by a physician experienced in stroke care using only the accounts of the patient and observers. There are mainly 3 different large categories of worsening: (1) Medical complications, especially febrile illnesses, which affect the patient systemically and may also lead to increased brain ischemia. These complications usually do not develop on the day of admission, and these patients are sick …

Ischemic stroke is the leading cause of disability and death worldwide. Currently, the only proven treatment for ischemic stroke is restoring the cerebral blood supply. In addition, some of the tissue is damaged during the subsequent reperfusion because of the overproduction of reactive oxygen species (ROS). Furthermore, antioxidant therapies have shown promise in preclinical studies for the treatment of ischemia-reperfusion injury. However, their therapeutic efficacy has been limited because of their low bioavailability in brain. To resolve this issue, we synthesized ROS-responsive, fan-shaped dendrimer nanoparticles (NPs) and conjugated them with a blood-brain barrier (BBB)-targeting peptide, COG1410, and salvianic acid A (SA), which is an effective antioxidant in ischemic stroke. The BBB targeting peptide acts as a ligand of the nanocarrier system and penetrates the BBB through the endocytosis of the ligand receptor. The results showed that T-SA-NPs not only target and accumulate in the infarct area, they also reduce over 2 times of the infarct area and reverse the behavioral deficits in MCAO mice, which illustrates that these NPs have an effective therapeutic effect on the ischemic stroke. In addition, these NPs had no toxicity in any organs of the body. Importantly, the present study provides an alternative strategy for delivering antioxidants to the brain and achieving targeted therapy of ischemic stroke.

Intracranial bleeding is the most feared complication of thrombolytic therapy in acute stroke. The risk of brain hemorrhage is the main argument of the European authorities not to approve recombinant tissue plasminogen activator (rtPA), and the fear of hurting patients with rtPA explains its limited use in North America. The common argument is, “Treatment with rt-PA may have some beneficial effect, but that is traded off by a considerable risk of symptomatic hemorrhage.” This argument is false and based on misunderstanding and misconception. The misunderstanding: There is no such trade-off. The National Institute of Neurological Disorders and Stroke (NINDS) rtPA Stroke Study Group observed 2 patients (0.6%) with symptomatic and 1 patient (0.3%) with fatal hemorrhages in the placebo group (n=312) and 20 patients (6.4%) with symptomatic and 9 patients (2.9%) with fatal hemorrhages in the rtPA group (n=312).1 Despite this supposed excess in risks caused by rtPA treatment (odds ratios [OR], 10.6 and 9.2), rtPA treatment significantly reduced the risk for disability and death (modified Rankin Scale >1 at 12 months after stroke) from 73% to 59% (reduction for death alone: 28% to 24%).2 In both European Cooperative Acute Stroke Studies (ECASS) 1 and 2, rtPA increased the risk for parenchymal hematomas (OR, 3.0 and 4.2), but reduced the overall risk for disability and death by 6% and 8% (NS).3,4⇓ A similar observation—an overall risk reduction for disability and death despite an increased risk for intracranial hemorrhages—was made in the Multicenter Acute Stroke Trials (MAST) -Europe and -Italy. Why …

Background: Every year, strokes take millions of lives and leave millions of individuals living with permanent disabilities. Recently more researchers embrace the concept of the neurovascular unit (NVU), which encompasses neurons, endothelial cells (ECs), pericytes, astrocyte, microglia, and the extracellular matrix. It has been well-documented that NVU emerged as a new paradigm for the exploration of mechanisms and therapies in ischemic stroke. To better understand the complex NVU and broaden therapeutic targets, we must probe the roles of multiple cell types in ischemic stroke. The aims of this paper are to introduce the biological characteristics of brain pericytes and the available evidence on the diverse functions and mechanisms involving the pericytes in the context of ischemic stroke.Methods: Research and online content related to the biological characteristics and pathophysiological roles of pericytes is review. The new research direction on the Pericytes in ischemic stroke, and the potential therapeutic targets are provided.Results: During the different stages of ischemic stroke, pericytes play different roles: 1) On the hyperacute phase of stroke, pericytes constriction and death may be a cause of the no-reflow phenomenon in brain capillaries; 2) During the acute phase, pericytes detach from microvessels and participate in inflammatory-immunological response, resulting in the BBB damage and brain edema. Pericytes also provide benefit for neuroprotection by protecting endothelium, stabilizing BBB and releasing neurotrophins; 3) Similarly, during the later recovery phase of stroke, pericytes also contribute to angiogenesis, neurogenesis, and thereby promote neurological recovery.Conclusion: This emphasis on the NVU concept has shifted the focus of ischemic stroke research from neuro-centric views to the complex interactions within NVU. With this new perspective, pericytes that are centrally positioned in the NVU have been widely studied in ischemic stroke. More work is needed to elucidate the beneficial and detrimental roles of brain pericytes in ischemic stroke that may serve as a basis for potential therapeutic targets.

An Update on Neurocritical Care for the Patient With Kidney Disease

Stroke is the third leading cause of death and a leading cause of adult disability in the United States.1 From a global perspective, stroke is also a leading cause of death and disability. The past 20 years have seen significant improvements in stroke prevention, yet each year, >700 000 people have a new or recurrent stroke.2,3 The medical and societal costs of stroke exceed $62 billion in the United States alone.4 Any intervention that could reverse or limit the effects of a stroke would have dramatic medical, societal, and public health benefits. This section will focus on treatment of acute ischemic stroke, which accounts for 80% to 85% of all strokes. Other recent publications have focused on therapies for intracerebral hemorrhage. Acute interventions to reduce the effects of an ischemic stroke can be organized into several main approaches: (1) reperfusion strategies (lytics, endovascular/mechanical); (2) neuroprotection; and (3) restoration, regeneration, and rehabilitation. ### Medical Therapies Thrombolytic therapies for acute ischemic stroke have been used or under study for 30 to 40 years, yet only recently has an agent been approved by the US Food and Drug Administration (FDA) and included in the treatment guidelines. Intravenous recombinant tissue plasminogen activator (rtPA) is the only FDA-approved medical therapy proven to reduce the effects of an ischemic stroke.5,6 Its main mechanism of action is to lyse a clot that is occluding a cerebral vessel, thereby reperfusing distal ischemic brain tissue and preventing or limiting the area of cell death and tissue necrosis. The efficacy of intravenous rtPA was proven in the pivotal National Institute of Neurological Disorders and Stroke (NINDS) rtPA study, which showed improved outcomes for patients treated within 3 hours of stroke onset.7 The NINDS tissue plasminogen activator (tPA) trial had an efficacy end point that was equivalent to the …

Section Editors: Marc Fisher MD Antoni Davalos MD The Food and Drug Administration (FDA) evaluates applications for new human drugs, biologics, and complex medical devices. Companies must obtain FDA approval to legally market these products. In August, the FDA gave Concentric Medical clearance to market its Merci Retriever system to “remove blood clots from the brain in patients experiencing an ischemic stroke.” Given that the FDA is charged with “protecting the public health by assuring the safety, efficacy, and security of… biological products and medical devices…, ” “advancing public health by helping to speed innovations that make medicines … more effective, safer, and more affordable,” and “helping the public get the accurate, science-based information they need to use medicines … to improve their health,”1 the FDA’s decision to approve the Merci Retriever system is of concern. The pathways to approval are reviewed by Felten et al in the accompanying article and are outlined in Figure 1. Figure 1. Potential pathways for device approval. The decision to approve the Merci Retriever was based on data from the MERCI (Mechanical Embolus Removal in Cerebral Ischemia) Trial; the approval was granted through the 510(k) process. The Merci Retriever system includes a flexible nickel titanium (nitinol) wire that obtains a helical shape once it is passed through the tip of the guidance catheter. In practice, the catheter/wire is passed distal to the thrombus, the catheter is removed, and the helical configuration assumed by the wire; the clot is then trapped in the helix and withdrawn from the vasculature (Figure 2). The 510(k) clearance means that the Merci Retriever was felt to be substantially equivalent to a predicate device. In this case, the predicate device was the Concentric Retriever, which itself received 510(k) clearance by the FDA in May 2001 for “use in …

To the Editor: We read with interest the report by Bereczki and colleagues,1 who failed to find evidence supporting the use of mannitol in acute stroke after a thorough search of the available medical literature. The authors found only one “unconfounded” randomized clinical trial evaluating mannitol in stroke. Not surprisingly, mannitol holds a preeminent position in the limited clinical armamentarium of neurological critical care, despite the virtual absence of well-designed studies addressing its role in stroke. The rationale of osmotherapy in brain ischemia is mainly inferred from two circumstances: (1) brain edema is intricately involved in cellular damage during ischemia and (2) the blood-brain barrier (BBB) remains basically intact during the first few hours after the onset of ischemia. Perivascular glial edema occurs within minutes after the induction of ischemia and is followed by neuronal edema.2 Due to the small pore size of cerebral endothelium, the BBB has a very low hydraulic conductivity, which limits the passage of small molecules and even restricts the permeability of water.3 A hydrostatic pressure gradient across the BBB develops early after ischemia, leading to the accumulation of interstitial fluid.4 In addition, …

Stroke is the second leading cause of death and the third leading cause of disability worldwide, with ischemic stroke (IS) being the most prevalent. A substantial number of irreversible brain cell death occur in the short term, leading to impairment or death in IS. Limiting the loss of brain cells is the primary therapy target and a significant clinical issue for IS therapy. Our study aims to establish the gender specificity pattern from immune cell infiltration and four kinds of cell-death perspectives to improve IS diagnosis and therapy. Combining and standardizing two IS datasets (GSE16561 and GSE22255) from the GEO database, we used the CIBERSORT algorithm to investigate and compare the immune cell infiltration in different groups and genders. Then, ferroptosis-related differently expressed genes (FRDEGs), pyroptosis-related DEGs (PRDEGs), anoikis-related DEGs (ARDEGs), and cuproptosis-related DEGs (CRDEGs) between the IS patient group and the healthy control group were identified in men and women, respectively. Machine learning (ML) was finally used to generate the disease prediction model for cell death-related DEGs (CDRDEGs) and to screen biomarkers related to cell death involved in IS. Significant changes were observed in 4 types of immune cells in male IS patients and 10 types in female IS patients compared with healthy controls. In total, 10 FRDEGs, 11 PRDEGs, 3 ARDEGs, and 1 CRDEG were present in male IS patients, while 6 FRDEGs, 16 PRDEGs, 4 ARDEGs, and 1 CRDEG existed in female IS patients. ML techniques indicated that the best diagnostic model for both male and female patients was the support vector machine (SVM) for CDRDEG genes. SVM's feature importance analysis demonstrated that SLC2A3, MMP9, C5AR1, ACSL1, and NLRP3 were the top five feature-important CDRDEGs in male IS patients. Meanwhile, the PDK4, SCL40A1, FAR1, CD163, and CD96 displayed their overwhelming influence on female IS patients. These findings contribute to a better knowledge of immune cell infiltration and their corresponding molecular mechanisms of cell death and offer distinct clinically relevant biological targets for IS patients of different genders.

Stroke is the second-leading cause of death and the leading cause of disability in much of the world. In particular, China faces the greatest challenge from stroke, since the population...

Tobacco smoking is a preventable risk factor for ischemic stroke in both males and females and contributes up to 14% of all stroke deaths. It has been reported that an increase in brain edema after ischemic stroke worsens long‐term clinical outcome, such as seen in tobacco smokers. Myo‐inositol (MI) is a major organic “non‐perturbing” osmolyte that promotes cell membrane stability and also a precursor for phosphoinositide signaling pathway. Our previous work reported that MI attenuated brain infarct and edema ratio in an ischemic stroke model coupled to preclinical diabetes and suggests that MI and MI transporters provide neuroprotection during/following stroke both in non‐diabetic and diabetic conditions through protection from brain edema. Since our lab has shown that tobacco smoke exposure worsens stroke edema similarly to diabetic conditions, the aim of the present study was to assess the neuroprotective effects of MI associated with ischemic mice exposed to tobacco smoke. In this study, we also investigated the role of MI transporters during stroke and post‐stroke outcomes especially related to the role of astrocytes cells, which are the most abundant glial cells in the brain and play an important role in post‐stroke reorganization, and indirectly protecting neuronal metabolic support. Primary mouse astrocytes were incubated with tobacco smoke extract (TSE) overnight prior for in vitro studies. Toxicity of TSE was measured using MTT assay after incubating astrocytes with TSE 6hr and 24hr. Therapeutic efficacy of MI was evaluated in a transient‐middle cerebral artery occlusion (tMCAO) mouse model after smoking 3R4F research cigarettes for 10 days. Uptake studies showed an increase of MI uptake increased with longer incubation of TSE in normoxic conditions. Additionally, it was also observed that uptake of MI increased during Oxygen Glucose Deprivation(OGD) conditions with prior exposure of TSE. These results are in support with our previous reports, where we found an increased expression of MI transports, Sodium Myo‐inositol Transporter 1 (SMIT1) and Sodium Dependent Glucose Transporter 6 (SGLT6) during OGD exposure. Preliminary animal studies using middle cerebral artery occlusion mouse model for in vivo stroke studies, demonstrated that post‐stroke administration of MI attenuated infarction size and edema ratios in tobacco smoke exposed animals compared to non‐tobacco smoked ischemic animals and also improved motor function in behavioral tests. Taken together with previous work, this study provides an insight into how MI may play a neuroprotective role in ischemic stroke injury and could significantly improve stroke outcome, especially in tobacco smoke populations. Further studies are required to understand the neuroprotective mechanisms of MI in ischemic stroke injury in reducing brain edema.Support or Funding InformationR01NS076012 and R01DA029121This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

CKLF1 is a chemokine with increased expression in ischemic brain, and targeting CKLF1 has shown therapeutic effects in cerebral ischemia model. Microglia/macrophage polarization is a mechanism involved in poststroke injury expansion. Considering the quick and obvious response of CKLF1 and expeditious evolution of stroke lesions, we focused on the effects of CKLF1 on microglial/macrophage polarization at early stage of ischemic stroke (IS). The present study is to investigate the CKLF1-mediated expression of microglia/macrophage phenotypes in vitro and in vivo, discussing the involved pathway. Primary microglia culture was used in vitro, and mice transient middle cerebral artery occlusion (MCAO) model was adopted to mimic IS. CKLF1 was added to the primary microglia for 24h, and we found that CKLF1 modulated primary microglia skew toward M1 phenotype. In mice transient IS model, CKLF1 was stereotactically microinjected to the lateral ventricle of ischemic hemisphere. CKLF1 aggravated ischemic injury, accompanied by promoting microglia/macrophage toward M1 phenotypic polarization. Increased expression of pro-inflammatory cytokines and decreased expression of anti-inflammatory cytokines were observed in mice subjected to cerebral ischemia and administrated with CKLF1. CKLF1-/- mice were used to confirm the effects of CKLF1. CKLF1-/- mice showed lighter cerebral damage and decreased M1 phenotype of microglia/macrophage compared with the WT control subjected to cerebral ischemia. Moreover, NF-κB activation enhancement was detected in CKLF1 treatment group. Our results demonstrated that CKLF1 is an important mediator that skewing microglia/macrophage toward M1 phenotype at early stage of cerebral ischemic injury, which further deteriorates followed inflammatory response, contributing to early expansion of cerebral ischemia injury. Targeting CKLF1 may be a novel way for IS therapy.

MicroRNAs have been discovered as regulators of gene expression and thus their potential in clinical disease diagnostics, prognosis and therapy is being actively pursued. MicroRNAs play an important role in atherosclerosis-related diseases, such as cerebrovascular and cardiovascular disease. However, the effect of miR-185 and miR-146a on patients with ischemic stroke (IS) in the different phases has not been reported. In this study, we investigated the amounts of three miRNAs, miR-185, miR-146a, and miR-145 in blood circulation of IS patients. We enrolled 60 patients with IS in the acute or sub-acute phase and 30 healthy controls. We divided the patients into two groups, patients with ischemic stroke in the acute phase (ISA) and patients with ischemic stroke in the subacute phase (ISS). We measured circulating miRNAs expression by miRNA microarray and real-time polymerase chain reaction (PCR) analysis. Testing by miRNA microarray and RT-PCR analyses showed that miR-145 levels in healthy subjects were similar to patients with IS, whereas miR-146a and miR-185 were present with quite low abundance in ISA compared with healthy individuals; moreover, we found that miR-146a levels were downregulated in ISA but upregulated in ISS which may help provide new insights into the diagnosis and therapy of IS.

Hydroxychloroquine (HCQ), a well-known antimalarial and anti-inflammatory drug, has demonstrated potential neuroprotective effects in ischemic stroke by inhibiting pyroptosis, a programmed cell death associated with inflammation. This study investigates the impact of HCQ on ischemic stroke pathology using both in vivo and in vitro models. In vivo, C57BL/6 mice subjected to middle cerebral artery occlusion (MCAO) were treated with HCQ. Neurological deficits, infarct volume, and the expression of pyroptosis markers were evaluated. The results demonstrated that HCQ significantly improved motor function and reduced infarct volume in the MCAO mouse model. In vitro, BV2 microglial cells exposed to lipopolysaccharide (LPS) and oxygen-glucose deprivation (OGD) were treated with HCQ. Western blot and immunofluorescence analyses revealed that HCQ effectively suppressed the expression of pyroptosis markers GSDMD and NLRP3 in both in vivo and in vitro models. These findings suggest that HCQ mitigates ischemic stroke damage by inhibiting pyroptosis, highlighting its potential as a therapeutic agent for ischemic stroke. This study provides novel insights into the molecular mechanisms by which HCQ exerts its neuroprotective effects, offering a promising new avenue for developing safe, cost-effective, and widely applicable stroke treatments. The potential of HCQ to modulate neuroinflammatory pathways presents a significant advancement in ischemic stroke therapy, emphasizing the importance of targeting pyroptosis in stroke management and the broader implications for treating neuroinflammatory conditions.Significance Statement Ischemic stroke remains a leading cause of disability and death globally, with limited effective treatments. This study reveals that HCQ significantly mitigates ischemic stroke damage by inhibiting pyroptosis, a form of programmed cell death. Using in vivo and in vitro models, HCQ was shown to improve motor function and reduce infarct volume, highlighting its potential as a neuroprotective agent. These findings offer a promising new therapeutic approach for ischemic stroke, emphasizing the importance of targeting pyroptosis in stroke treatment.