Therapeutic time window for treatment of focal cerebral ischemia reperfusion injury with XQ-1h in rats

Neuroprotective Effects of Deproteinized Calf Serum in Ischemic Stroke

Deproteinized calf serum (DCS) may have neuroprotective effects after ischemic stroke. The aim of this study is to investigate whether and how the DCS inhibits neuronal injury following cerebral ischemia. Rats were subjected to 2 h transient middle cerebral artery occlusion (MCAO). One dose of 0.125 mg/gbw DCS was given immediately after reperfusion. Neurological deficit and infarct volume at 24 h post-MCAO in DCS-treated rats were lower than those in vehicle-treated rats (p < 0.0005). In cultured neurons model, cell viability was decreased, and apoptosis was increased by oxygen-glucose deprivation/reperfusion (OGD/R) (p < 0.0005). These effects of OGD/R were attenuated by 0.4 μg/μl DCS (p < 0.05) that were validated by CCK8 cell viability assay, phycoerythrin–Annexin V Apoptosis Detection assay, and TUNEL assay. Furthermore, the increase of intracellular ROS level in cultured neurons was suppressed by DCS (p < 0.05). Compared with cells subjected to OGD/R, the expression level of Bax protein decreased, and bcl-2 protein increased after DSC treatment (p < 0.05). Overall, the neuroprotective effects of DCS following cerebral ischemia may in part be due to decreased ROS production and inhibition of apoptosis.

Emerging neuroprotective strategies for the treatment of ischemic stroke: An overview of clinical and preclinical studies

Stroke is the leading cause of disability and thesecond leading cause of death worldwide. With the global population aged 65 and over growing faster than all other age groups, the incidence of stroke is also increasing. In addition, there is a shift in the overall stroke burden towards younger age groups, particularly in low and middle-income countries. Stroke in most cases is caused due to an abrupt blockage of an artery (ischemic stroke), but in some instances stroke may be caused due to bleeding into brain tissue when a blood vessel ruptures (hemorrhagic stroke). Although treatment options for stroke are still limited, with the advancement in recanalization therapy using both pharmacological and mechanical thrombolysis some progress has been made in helping patients recover from ischemic stroke. However, there is still a substantial need for the development of therapeutic agents for neuroprotection in acute ischemic stroke to protect the brain from damage prior to and during recanalization, extend the therapeutic time window for intervention and further improve functional outcome. The current review has assessed the past challenges in developing neuroprotective strategies, evaluated the recent advances in clinical trials, discussed the recent initiative by the National Institute of Neurological Disorders and Stroke in USA for the search of novel neuroprotectants (Stroke Preclinical Assessment Network, SPAN) and identified emerging neuroprotectants being currently evaluated in preclinical studies. The underlying molecular mechanism of each of the neuroprotective strategies have also been summarized, which could assist in the development of future strategies for combinational therapy in stroke treatment.

XQ-1H regulates Wnt/GSK3β/β-catenin pathway and ameliorates the integrity of blood brain barrier in mice with acute ischemic stroke

10-O-(N, N-dimethylaminoethyl) ginkgolide B methanesulfonate (XQ-1H), a novel analog of ginkgolide B, has been preliminarily recognized to show bioactivities against ischemia-induced injury. However, the underlying mechanism still remains to be fully elucidated. The aim of this study was to investigate the effect of XQ-1H against cerebral ischemia/reperfusion injury (CIRI) from the perspective of blood brain barrier (BBB) protection, and explore whether the underlying mechanism is associated with Wnt/GSK3β/β-catenin signaling pathway activation. The therapeutic effects of XQ-1H were evaluated in mice subjected to middle cerebral artery occlusion/reperfusion (MCAO/R) and in immortalized mouse cerebral endothelial cells (bEnd.3) challenged by oxygen and glucose deprivation/reoxygenation (OGD/R). Results showed that treatment with XQ-1H improved neurological behavior, reduced brain infarction volume, diminished edema, and attenuated the disruption of BBB in vivo. In vitro, XQ-1H increased cell viability and maintained the barrier function of bEnd.3 monolayer after OGD/R. Moreover, the protection of XQ-1H was accompanied with activation of Wnt/GSK3β/β-catenin pathway and upregulation of tight junction proteins. Notably, the protection of XQ-1H was abolished by Wnt/GSK3β/β-catenin inhibitor XAV939 or β-catenin siRNA, indicating XQ-1H exerted protection in a Wnt/GSK3β/β-catenin dependent profile. In summary, XQ-1H attenuated brain injury and maintained BBB integrity after CIRI, and the possible underlying mechanism may be related to the activation of Wnt/GSK3β/β-catenin pathway and upregulation of tight junction proteins.

The effect of intravenous ginkgolide on clinical improvement of patients with acute ischemic stroke

Aims: To compare the efficacy of ginkgolide in the treatment of Chinese patients with ischemic stroke between pre-marketing and post-marketing studies.Methods: This is a re-analysis of a pre-marketing (phase II/III, multicenter, double-blind, parallel-controlled; February 2005 to September 2005) and post-marketing (phase IV, multicenter, open, single-arm registration; April 2013 to June 2014) studies. The intervention groups received intravenous ginkgolide (10 mL daily, 14 days). Primary outcome was an improvement of National Institute of Health Stroke Scale (NIHSS) and modified Rankin Scale (mRS) scores after 14 days.Results: In pre- and post-marketing studies, NIHSS and mRS scores all improved, compared to that of baseline (P < 0.001) in acute phase. Those factors significantly associated with △NIHSS after 14 days of therapy with ginkgolide were grouping (pre-marketing vs. post-marketing; OR 2.169, 95%CI = 1.462-3.216, P < 0.001), male (OR = 1.532, 95%CI = 1.152-2.037, P = 0.003), enrollment within 30 days after onset (OR = 1.915, 95%CI = 1.452-2.526, P < 0.001) and NIHSS score more than 8 points at baseline (OR = 15.140, 95%CI = 11.436-20.045, P < 0.001) after adjustment. Ginkgolide had a greater effect on patients in a relatively acute phase (time of onset to enrollment ≤30 days) and moderate-severe stroke (baseline NIHSS>8 points). Incidences of adverse reactions in the pre-marketing and post-marketing studies were 0.46% and 5.28%, respectively (P < 0.001).Conclusion: Intravenous ginkgolide may improve the outcome of acute ischemic stroke. Differences in effect between pre-marketing and post-marketing studies may be associated with gender, time of onset to enrollment and severity of stroke.

Pharmacokinetics and pharmacodynamics analysis of XQ-1H and its combination therapy with clopidogrel on cerebral ischemic reperfusion injury in rats

Ischemic stroke is the main cause of disability and mortality worldwide. 10-O-(N N-dimethylaminoethyl)-ginkgolide B methane-sulfonate (XQ-1 H) is a novel drug based on the remedial approach for ischemic stroke. Clopidogrel, a widely used anti-platelet drug, is often co-prescribed in the clinic. In this study, we established an UPLC-MS/MS spectrometry method for the determination of XQ-1H and investigated the pharmacokinetic effect of clopidogrel on XQ-1H in rats subjected to middle cerebral artery occlusion (MCAO). Meanwhile, the anti-apoptotic and neuroprotective effects of XQ-1H and its combination with clopidogrel were also studied. The results revealed that XQ-1H and its combination with clopidogrel abridged brain infarct volume, cerebral edema and alleviated neurological dysfunction caused by cerebral ischemic reperfusion injury. Further study demonstrated that XQ-1H combined with clopidogrel lessened TUNEL positive cells, up-regulated bcl-2 expression notably and down-regulated bax expression as compared to both XQ-1H and clopidogrel individually. In addition, a rapid, sensitive UPLC-MS/MS method was developed to quantify the concentration of XQ-1H in MCAO/R rats. Our pharmacokinetic results showed that clopidogrel significantly increased the exposure of XQ-1H, increased the peak plasma concentration (C_max), area under the curve (AUC) and slowed elimination of XQ-1H in the co-administered group. Besides, for further exploring which CYP450 isoforms are involved in the XQ-1H metabolism, XQ-1H was incubated in human liver microsomes (HLMs) system with or without P450 isoform-selective inhibitors. Our results revealed that clopidogrel altered pharmacokinetics of XQ-1H potentially and subsequently enhanced the pharmacological effect of XQ-1H. Moreover, XQ-1H could be applied as an efficacious neuroprotective agent for ischemic stroke because of its considerable effect on averting neuronal apoptosis.

XQ-1H alleviates cerebral ischemia in mice through inhibition of apoptosis and promotion of neurogenesis in a Wnt/β-catenin signaling dependent way

AIMS

10-O-(N,N-dimethylaminoethyl)-ginkgolide B methanesulfonate (XQ-1H), a new derivative of ginkgolide B, has drawn great attention for its potent bioactivities against ischemia-induced injury. The purpose of this study was to further investigate the effect of XQ-1H against acute ischemic stroke by inducing middle cerebral artery occlusion/reperfusion (MCAO/R) injuries in mice.

MAIN METHODS

Treatment of XQ-1H (78 or 39 mg/kg, i.g., bid) 2 h after MCAO improved motor skills and ameliorated the severity of brain infarction and apoptosis seen in the mice by diminishing pathological changes and the activation of a pro-apoptotic protein Cleaved-Caspase-3, which in turn induced anti-apoptotic Bcl-xL. Through introducing Wnt/β-catenin signaling inhibitor XAV-939, XQ-1H was proven to intensively promoted neurogenesis in the peri-infarct cortex, subventricular area (SVZ) and the dentate gyrus (DG) subgranular area (SGZ) in a Wnt signal dependent way by compromising the activation of GSK3β, which in turn upregulated Wnt1, β-catenin, Neuro D1 and Cyclin D1, most possibly through the activation of PI3K/Akt signaling via the upregulation of brain-derived neurotrophic factor (BDNF) and nerve growth factor (NGF).

KEY FINDINGS

We conclude that XQ-1H preserved the motor functions, limited apoptosis, and concomitantly promoted neurogenesis-related protein expression by Wnt signaling-dependently compromising GSK3β/Caspase-3 activity and enhancing the expression of Wnt1/β-catenin/Neuro D1/Cyclin D1 and Bcl-xL.

SIGNIFICANCE

This research may benefit the development of stroke therapeutics targeting neurogenesis through Wnt upregulation by XQ-1H.

Neuroprotection by combination of resveratrol and enriched environment against ischemic brain injury in rats

OBJECTIVES

Both resveratrol (RV) and enriched environment (EE) exert beneficial effects on neurological functional recovery after an ischemic brain injury.

METHODS

The neuroprotective effect of combined treatment of RV and EE was examined in a rat model of middle cerebral artery occlusion (MCAO), aiming to further promote neurological functional recovery.

RESULTS

The combined therapy of RV and EE clearly improved locomotor activity and behaviour examination, compared to the monotherapy of RV or EE alone. Stroke severity was also markedly ameliorated by the co-treatment. Mechanistic study revealed that the combined treatment reduced oxidative stress. Moreover, the detrimental ERK1/2 signalling upregulated by MCAO injury was markedly suppressed by the co-treatment, compared to RV or EE monotherapy.

DISCUSSION

Altogether, the combined therapy of RV and EE showed a clearly enhanced neuroprotective effect, compared to RV or EE monotherapy, which might be a new strategy for the treatment of ischemic brain injury.

XQ-1H Suppresses Neutrophils Infiltration and Oxidative Stress Induced by Cerebral Ischemia Injury Both In Vivo and In Vitro

Cerebral ischemia/reperfusion injury plays an important role in the development of tissue injury after acute stroke, including neutrophils adhesion and infiltration, inflammation and oxidative stress. 10-O-(N,N-dimethylaminoethyl)-ginkgolide B methanesulfonate (XQ-1H) is a novel ginkdolide B derivative. In this study, we investigated the anti-inflammatory and anti-oxidative activities of XQ-1H in vivo and vitro. In our study, rats were treating with XQ-1H (31.2, 15.6 and 7.8 mg/kg) after middle cerebral artery occlusion surgery. Primary cultured cortical rat neurons were treated with Na2S2O4 for 1.5 h to mimic hypoxia and reoxygenation injury in vitro. Cortical neurons were preincubated with XQ-1H (100, 10, 1 μM) 24 h before hypoxic injury. Brain edema was evaluated by brain water content. Neutrophil infiltration was determined by fluorescence imaging method and myeloperoxidase assay. Intercellular adhesion molecule 1 (ICAM-1) and matrix metallopeptidase 9 (MMP-9) expressions were examined by immunohistochemistry analysis. Neuronal injury was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide, lactate dehydrogenase releasing and lactic acid content. The anti-oxidative effects of XQ-1H were evaluated by superoxide dismutase (SOD) activity and malondialdehyde content in ischemic brain and neuron cultures subjected to hypoxia/reoxygenation procedure. Results showed that XQ-1H reduced neutrophils infiltration to ischemic brain, which might result from down regulation of inflammatory mediators, such as ICAM-1 and MMP-9. In addition, an antioxidative effect of XQ-1H was observed in cortical neuron and brain homogenates by enhancing SOD activity and inhibiting lipid peroxidation. These results indicated that XQ-1H possessed a protective effect against cerebral ischemia, especially on neutrophil infiltration and oxidative stress.

Method parameters' impact on mortality and variability in rat stroke experiments: a meta-analysis

Background

Even though more than 600 stroke treatments have been shown effective in preclinical studies, clinically proven treatment alternatives for cerebral infarction remain scarce. Amongst the reasons for the discrepancy may be methodological shortcomings, such as high mortality and outcome variability, in the preclinical studies. A common approach in animal stroke experiments is that A) focal cerebral ischemia is inflicted, B) some type of treatment is administered and C) the infarct sizes are assessed. However, within this paradigm, the researcher has to make numerous methodological decisions, including choosing rat strain and type of surgical procedure. Even though a few studies have attempted to address the questions experimentally, a lack of consensus regarding the optimal methodology remains.

Methods

We therefore meta-analyzed data from 502 control groups described in 346 articles to find out how rat strain, procedure for causing focal cerebral ischemia and the type of filament coating affected mortality and infarct size variability.

Results

The Wistar strain and intraluminal filament procedure using a silicone coated filament was found optimal in lowering infarct size variability. The direct and endothelin methods rendered lower mortality rate, whereas the embolus method increased it compared to the filament method.

Conclusions

The current article provides means for researchers to adjust their middle cerebral artery occlusion (MCAo) protocols to minimize infarct size variability and mortality.

Therapeutic neuroprotective effects of XQ-1H in a rat model of permanent focal cerebral ischemia

Cerebral ischemia is one of the leading causes for death and severe disabilities in the world. XQ-1H exerts neuroprotective effects under various neurotoxic conditions in vitro. In vivo, it reduces brain damage after transient focal cerebral ischemia. The present study evaluated the dose effectiveness and therapeutic time window of neuroprotection of XQ-1H by behavioral and histological measures in rats subjected to permanent middle cerebral artery occlusion (pMCAO). Neurological deficits, TTC stain, brain water content, necrosis neuron counts, and Evans-Blue extravasation were used to quantify brain damage and blood-brain barrier dysfunction. Our results demonstrated that postischemic treatment with XQ-1H at a dose of 31.2 mg/kg produced a significant reduction in neurological scores when treatment was initiated within 2 h of pMCAO. A similar improvement was also observed in infarct volume, brain water content, Evans-Blue extravasation, and neuronal necrosis when treatment was initiated within 1 h of pMCAO. Treatment with XQ-1H at the dose of 15.6 mg/kg within 1 h also produced significant improvement in ischemia deficit. In conclusion, the therapeutic time window of XQ-1H extends for up to 1 h after pMCAO, and treatment with XQ-1H exhibits potent neuroprotection that may be of value for the design of stroke therapies.