Protective effect of furofuranone against cerebral ischemic stroke via activation of PI3k/Akt/GSK 3β signaling pathway

Purpose: To study the protective effects of furofuranone on oxygen and glucose-deprived damage to brain microvascular endothelial cells (BMECs) in vitro, and in vivo in cerebral ischemic stroke rat model. Methods: BMECs were isolated from the Sprague Dawley rats and deprived of oxygen and glucose. The effect of 10, 20, 30, 40, 50 and 100 µM furofuranone on the oxygen/glucose-deprived BMECs was studied using Transwell chamber method. A rat cerebral ischemic stroke model was established using middle cerebral arterial occlusion method. Caspase-3 and other proteins, inflammatory cytokines, and other parameters of the brain tissue were evaluated by enzyme-linked assay (ELISA), polymerase chain reaction (PCR) and Western blot as appropriate. Further studies on the brain tissues was carried out by immunochemical analysis and hematoxylin and eosin staining. Results: Furofuranone decreased caspase 3 levels in a dose-based manner in rat BMECs, and significantly reduced the release of lactate dehydrogenase (LDH) in ischemic stroke rat model (p < 0.05). It also led to marked increases in the levels of p PI3k, p Akt and p GSK3β in cerebral ischemic stroke rats. Growth-associated protein-43 (GAP-43) and microtubule-associated protein 2 (MAP-2) levels increased in the cerebral ischemic stroke rat brain tissues, in addition to marked increase in ionized calcium-binding adaptor protein (IBA-1) and glial fibrillary acidic protein (GFAP) (p < 0.05). Furofuranone treatment reduced the population of microtubule-associated protein light chain 3 (MAP1LC3A) and Beclin 1-positive cells, and significantly downregulated L selectin, leptin, monocyte chemotactic protein-1 (MCP-1) and tumor necrosis factor (TNF)-α (p < 0.05). The release of tissue inhibitor of metalloproteinases 1 (TIMP-1) was enhanced in the cerebral ischemic stroke rats by furofuranone treatment. Conclusion: Furofuranone treatment prevents cerebral ischemic stroke-induced damage in rats via phosphorylation of PI3k, Akt and GSK3β proteins, and reduction of inflammatory cytokine levels. Therefore, furofuranone may be useful as chemotherapeutic agent for cerebral ischemic stroke

Enhanced Neuroprotective Effects by Inter-Ischemia Hypothermia in Cerebral Stroke

Background and Purpose. Studies have shown that inter-ischemia hypothermia is able to reduce the size of myocardial infarctions and improve their clinical outcomes. The present study determined whether inter-ischemia hypothermia induced by pharmacological approach induced stronger neuroprotection in ischemic brains. Methods. Adult male Sprague-Dawley rats were studied in 4 groups: (1) sham; (2) stroke; (3) stroke treated with pharmacological hypothermia before reperfusion (inter-ischemia hypothermia); and (4) stroke treated with pharmacological hypothermia after reperfusion is initiated (inter-reperfusion hypothermia). The combination of chlorpromazine and promethazine with dihydrocapsaicin was used to induce hypothermia. To compare the neuroprotective effects of drug-induced hypothermia between the groups, brain damage was evaluated using infarct volume and neurological deficits. In addition, mRNA expressions of NADPH oxidase subunits and glucose transporter subtypes were determined by real-time PCR. ROS production was measured by Flow cytometry assay at the same time points. Results: In both hypothermia groups, cerebral infarct volumes and neurological deficits were reduced. ROS production and the expressions of NOX subunits and glucose transporter subtypes were also significantly reduced in both hypothermia groups as compared to the ischemic group. While there were no statistically significant differences between the two hypothermia groups at 6 h reperfusion, brain damage was significantly further decreased by inter-ischemia hypothermia at 24 h. Conclusion: Inter-ischemia hypothermia and inter-reperfusion hypothermia after stroke induced neuroprotection by reducing oxidative injury, while neuroprotion was more effective with inter-ischemia hypothermia. This study provides a new avenue and reference for a stronger neuroprotective hypothermia before vascular recanalization in stroke patients

Fluorescent and photo-oxidizing TimeSTAMP tags track protein fates in light and electron microscopy.

Protein synthesis is highly regulated throughout nervous system development, plasticity and regeneration. However, tracking the distributions of specific new protein species has not been possible in living neurons or at the ultrastructural level. Previously we created TimeSTAMP epitope tags, drug-controlled tags for immunohistochemical detection of specific new proteins synthesized at defined times. Here we extend TimeSTAMP to label new protein copies by fluorescence or photo-oxidation. Live microscopy of a fluorescent TimeSTAMP tag reveals that copies of the synaptic protein PSD95 are synthesized in response to local activation of growth factor and neurotransmitter receptors, and preferentially localize to stimulated synapses in rat neurons. Electron microscopy of a photo-oxidizing TimeSTAMP tag reveals new PSD95 at developing dendritic structures of immature neurons and at synapses in differentiated neurons. These results demonstrate the versatility of the TimeSTAMP approach for visualizing newly synthesized proteins in neurons

Hypothermia in Stroke Therapy: Systemic versus Local Application

Presently, there are no effective, widely applicable therapies for ischemic stroke. There is strong clinical evidence for the neuroprotective benefits of hypothermia, and surface-cooling methods have been utilized for decades in the treatment of cerebral ischemia during cardiac arrest, but complications with hypothermia induction have hindered its clinical acceptance in ischemic stroke therapy. Recently, the microcatheter-based local endovascular infusion (LEVI) of cold saline directly to the infarct site has been proposed as a solution to the drawbacks of surface cooling. The safety and efficacy of LEVI in rat models have been established, and implementation in larger animals has been similarly encouraging. A recent pilot study even established the safety of LEVI in humans. This review seeks to outline the major research on LEVI, discusses the mechanisms that mediate its superior neuroprotection over surface and systemic cooling, and identifies areas that warrant further investigation. While LEVI features improvements on surface cooling, its core mechanisms of neuroprotection are still largely shared with therapeutic hypothermia in general. As such, the mechanisms of hypothermia-based neuroprotection are discussed as well

High Intensity Physical Rehabilitation Later Than 24 h Post Stroke Is Beneficial in Patients: A Pilot Randomized Controlled Trial (RCT) Study in Mild to Moderate Ischemic Stroke

Objective: Very early mobilization was thought to contribute to beneficial outcomes in stroke-unit care, but the optimal intervention strategy including initiation time and intensity of mobilization are unclear. In this study, we sought to confirm the rehabilitative effects of different initiation times (24 vs. 48 h) with different mobilization intensities (routine or intensive) in ischemic stroke patients within three groups.Materials and Methods: We conducted a randomized and controlled trial with a blinded follow-up assessment. Patients with ischemic stroke, first or recurrent, admitted to stroke unit within 24 h after stroke onset were recruited. Eligible subjects were randomly assigned (1:1:1) to 3 groups: Early Routine Mobilization in which patients received < 1.5 h/d out-of-bed mobilization within 24–48 h after stroke onset, Early Intensive Mobilization in which patients initiated ≥3 h/d mobilization at 24–48 h after the stroke onset, and Very Early Intensive Mobilization in which patients received≥3 h/d mobilization within 24 h. The modified Rankin Scale score of 0–2 was used as the primary favorable outcome.Results: We analyzed 248 of the 300 patients (80 in Early Routine Mobilization, 82 in Very Early Intensive Mobilization and 86 in Early Intensive Mobilization), with 52 dropping out (20 in Early Routine Mobilization, 18 in Very Early Intensive Mobilization and 14 in Early Intensive Mobilization). Among the three groups, the Early Intensive Mobilization group had the most favorable outcomes at 3-month follow-up, followed by patients in the Early Routine Mobilization group. Patients in Very Early Intensive Mobilization received the least odds of favorable outcomes. At 3 month follow up, 53.5%, (n = 46) of patients with Early Intensive Mobilization showed a favorable outcome (modified Rankin Scale 0–2) (p = 0.041) as compared to 37.8% (n = 31) of patients in the Very Early Intensive Mobilization.Conclusions: Post-stroke rehabilitation with high intensity physical exercise at 48 h may be beneficial. Very Early Intensive Mobilization did not lead to a favorable outcome at 3 months.Clinical Trial Registration:www.chictr.org.cn, identifier ChiCTR-ICR-15005992

Transient Stability of Epigenetic Population Differentiation in a Clonal Invader

Epigenetic variation may play an important role in how plants cope with novel environments. While significant epigenetic differences among plants from contrasting habitats have often been observed in the field, the stability of these differences remains little understood. Here, we combined field monitoring with a multi-generation common garden approach to study the dynamics of DNA methylation variation in invasive Chinese populations of the clonal alligator weed (Alternanthera philoxeroides). Using AFLP and MSAP markers, we found little variation in DNA sequence but substantial epigenetic population differentiation. In the field, these differences remained stable across multiple years, whereas in a common environment they were maintained at first but then progressively eroded. However, some epigenetic differentiation remained even after 10 asexual generations. Our data indicate that epigenetic variation in alligator weed most likely results from a combination of environmental induction and spontaneous epimutation, and that much of it is neither rapidly reversible (phenotypic plasticity) nor long-term stable, but instead displays an intermediate level of stability. Such transient epigenetic stability could be a beneficial mechanism in novel and heterogeneous environments, particularly in a genetically impoverished invader

Large vessel occlusion stroke outcomes in diabetic vs. non-diabetic patients with acute stress hyperglycemia

ObjectiveThis study assesses whether stress-induced hyperglycemia is a predictor of poor outcome at 3 months for patients with acute ischemic stroke (AIS) treated by endovascular treatment (EVT) and impacted by their previous blood glucose status.MethodsThis retrospective study collected data from 576 patients with AIS due to large vessel occlusion (LVO) treated by EVT from March 2019 to June 2022. The sample was composed of 230 and 346 patients with and without diabetes mellitus (DM), respectively, based on their premorbid diabetic status. Prognosis was assessed with modified Rankin Scale (mRS) at 3-month after AIS. Poor prognosis was defined as mRS>2. Stress-induced hyperglycemia was assessed by fasting glucose-to-glycated hemoglobin ratio (GAR). Each group was stratified into four groups by quartiles of GAR (Q1–Q4). Binary logistic regression analysis was used to identify relationship between different GAR quartiles and clinical outcome after EVT.ResultsIn DM group, a poor prognosis was seen in 122 (53%) patients and GAR level was 1.27 ± 0.44. These variables were higher than non-DM group and the differences were statistically significant (p < 0.05, respectively). Patients with severe stress-induced hyperglycemia demonstrated greater incidence of 3-month poor prognosis (DM: Q1, 39.7%; Q2, 45.6%; Q3, 58.6%; Q4, 68.4%; p = 0.009. Non-DM: Q1, 31%; Q2, 32.6%; Q3, 42.5%; Q4, 64%; p < 0.001). However, the highest quartile of GAR was independently associated with poor prognosis at 3 months (OR 3.39, 95% CI 1.66–6.96, p = 0.001), compared to the lowest quartile in non-DM patients after logistic regression. This association was not observed from DM patients.ConclusionThe outcome of patients with acute LVO stroke treated with EVT appears to be influenced by premorbid diabetes status. However, the poor prognosis at 3-month in patients with DM is not independently correlated with stress-induced hyperglycemia. This could be due to the long-term damage of persistent hyperglycemia and diabetic patients’ adaptive response to stress following acute ischemic damage to the brain

Nicotinamide adenine dinucleotide phosphate oxidase activation and neuronal death after ischemic stroke

Nicotinamide adenine dinucleotide phosphate oxidase (NOX) is a multisubunit enzyme complex that utilizes nicotinamide adenine dinucleotide phosphate to produce superoxide anions and other reactive oxygen species. Under normal circumstances, reactive oxygen species mediate a number of important cellular functions, including the facilitation of adaptive immunity. In pathogenic circumstances, however, excess reactive oxygen species generated by NOX promotes apoptotic cell death. In ischemic stroke, in particular, it has been shown that both NOX activation and derangements in glucose metabolism result in increased apoptosis. Moreover, recent studies have established that glucose, as a NOX substrate, plays a vital role in the pathogenesis of reperfusion injury. Thus, NOX inhibition has the potential to mitigate the deleterious impact of hyperglycemia on stroke. In this paper, we provide an overview of this research, coupled with a discussion of its implications for the development of NOX inhibition as a strategy for the treatment of ischemic stroke. Both inhibition using apocynin, as well as the prospect of developing more specific inhibitors based on what is now understood of the biology of NOX assembly and activation, will be highlighted in the course of our discussion