Prenatal and Postnatal Methyl-Modulator Intervention Corrects the Stress-Induced Glucocorticoid Response in Low-Birthweight Rats

Low body weight at birth has been shown to be a risk factor for future metabolic disorders, as well as stress response abnormalities and depression. We showed that low-birthweight rats had prolonged high blood corticosterone levels after stress exposure, and that an increase in Gas5 lncRNA, a decoy receptor for glucocorticoid receptors (GRs), reduces glucocorticoid responsiveness. Thus, we concluded that dampened pituitary glucocorticoid responsiveness disturbed the glucocorticoid feedback loop in low-birthweight rats. However, it remains unclear whether such glucocorticoid responsiveness is suppressed solely in the pituitary or systemically. The expression of Gas5 lncRNA increased only in the pituitary, and the intact induction of expression of the GR co-chaperone factor Fkbp5 against dexamethasone was seen in the liver, muscle, and adipose tissue. Intervention with a methyl-modulator diet (folate, VB12, choline, betaine, and zinc) immediately before or one week after delivery reversed the expression level of Gas5 lncRNA in the pituitary of the offspring. Consequently, it partially normalized the blood corticosterone levels after restraint stress exposure. In conclusion, the mode of glucocorticoid response in low-birthweight rats is impaired solely in the pituitary, and intervention with methyl-modulators ameliorates the impairment, but with a narrow therapeutic time window.

Peptide5 attenuates rtPA related brain microvascular endothelial cells reperfusion injury via the Wnt/β-catenin signalling pathway

Aims: Brain vascular endothelial cell dysfunction after rtPA treatment is a significant factor associated with poor prognosis, suggesting that alleviation of rtPA-related endothelial cell injury may represent a potential beneficial strategy along with rtPA thrombolysis. Background: Thrombolysis with recombinant tissue plasminogen activator (rtPA) is beneficial for acute ischemic stroke but may increase the risk of hemorrhagic transformation (HT), which is considered ischemia-reperfusion injury. The underlying reason may contribute to brain endothelial injury and dysfunction related to rtPA against ischemic stroke. As previous studies have demonstrated that transiently blocked Cx43 using peptide5 (Cx43 mimetic peptide) during retinal ischemia reduced vascular leakage, it is necessary to know whether this might help decrease side effect of rtPA within the therapeutic time window. Objective: This study aims to investigate the effects of peptide5 on rtPA-related cell injury during hypoxia/reoxygenation (H/R) within the therapeutic time window. Methods: In this study, we established a cell hypoxia/reoxygenation H/R model in cultured primary rat brain microvascular endothelial cells (RBMECs) and evaluated endothelial cell death and permeability after rtPA treatment with or without transient peptide5. In addition, we also investigated the potential signaling pathway to explore the underlying mechanisms preliminarily. Results: The results showed that peptide5 inhibited rtPA-related endothelial cell death and permeability. It also slightly increased tight junction (ZO-1, occluding, claudin-5) and β-catenin mRNA expression, demonstrating that peptide5 might attenuate endothelial cell injury by regulating the Wnt/β-catenin pathway. The following bioinformatic exploration from the GEO dataset GSE37239 was also consistent with our findings. Conclusion: This study showed that the application of peptide5 maintained cell viability and permeability associated with rtPA treatment, revealing a possible pathway that could be exploited to limit rtPA-related endothelial cell injury during ischemic stroke. Furthermore, the altered Wnt/β-catenin signaling pathway demonstrated that signaling pathways associated with Cx43 might have potential applications in the future. This study may provide a new way to attenuate HT and assist the application of rtPA in ischemic stroke.

Repeated Intravenous Thrombolysis in Patients with Recurrent Ischemic Stroke in the Vertebrobasilar Territory

Acute ischemic vertebrobasilar stroke (AIVBS) is usually associated with poor outcome and prognosis and in case of basilar artery occlusion (BAO) with high mortality. Intravenous thrombolysis (IVT), as a standard recanalization therapy of acute ischemic stroke (IS) within first 4.5 h, can be administrated beyond this therapeutic time window in case of symptomatic BAO. Repeated IVT is generally contraindicated in case of early recurrent IS, despite a risk of poor outcome or death after recurrent IS. The aim was to present 2 cases of repeated IVT for recurrent AIVBS and discuss specific situations where repeated IVT may be considered. Up to now, repeated IVT has been reported only in recurrent stroke in anterior circulation.

The Next Step in the Treatment of Stroke

Although many patients do not receive reperfusion therapy because of delayed presentation and/or severity and location of infarct, new reperfusion approaches are expanding the window of intervention. Novel application of neuroprotective agents in combination with the latest methods of reperfusion provide a path to improved stroke intervention outcomes. We examine why neuroprotective agents have failed to translate to the clinic and provide suggestions for new approaches. New developments in recanalization therapy in combination with therapeutics evaluated in parallel animal models of disease will allow for novel, intra-arterial deployment of therapeutic agents over a vastly expanded therapeutic time window and with greater likelihood success. Although the field of neuronal, endothelial, and glial protective therapies has seen numerous large trials, the application of therapies in the context of newly developed reperfusion strategies is still in its infancy. Given modern imaging developments, evaluation of the penumbra will likely play a larger role in the evolving management of stroke. Increasingly more patients will be screened with neuroimaging to identify patients with adequate collateral blood supply allowing for delayed rescue of the penumbra. These patients will be ideal candidates for therapies such as reperfusion dependent therapeutic agents that pair optimally with cutting-edge reperfusion techniques.

Early Electroacupuncture Extends the rtPA Time Window to 6 h in a Male Rat Model of Embolic Stroke via the ERK1/2-MMP9 Pathway

Background. Recombinant tissue plasminogen activator (rtPA) is the only recommended pharmacological treatment for acute ischemic stroke, but it has a restricted therapeutic time window. When administered at time points greater than 4.5 h after stroke onset, rtPA disrupts the blood-brain barrier (BBB), which leads to serious brain edema and hemorrhagic transformation. Electroacupuncture (EA) exerts a neuroprotective effect on cerebral ischemia; however, researchers have not clearly determined whether EA increases the safety of thrombolysis and extends the therapeutic time window of rtPA administration following ischemic stroke. Objective. The present study was conducted to test the hypothesis that EA extends the therapeutic time window of rtPA for ischemic stroke in a male rat model of embolic stroke. Methods. SD rats were randomly divided into the sham operation group, model group, rtPA group, EA+rtPA group, and rtPA+MEK1/2 inhibitor group. An injection of rtPA was administered 6 h after ischemia. Rats were treated with EA at the Shuigou (GV26) and Neiguan (PC6) acupoints at 2 h after ischemia. Neurological function, infarct volume, BBB permeability, brain edema, and hemorrhagic transformation were assessed at 24 h after ischemia. Western blotting and immunofluorescence staining were performed to detect the levels of proteins involved in the ERK1/2 signaling pathway (MEK1/2 and ERK1/2), tight junction proteins (Claudin5 and ZO-1), and MMP9 in the ischemic penumbra at 24 h after stroke. Results. Delayed rtPA treatment aggravated hemorrhagic transformation and brain edema. However, treatment with EA plus rtPA significantly improved neurological function and reduced the infarct volume, hemorrhagic transformation, brain edema, and EB leakage in rats compared with rtPA alone. EA increased the levels of tight junction proteins, inhibited the activation of the ERK1/2 signaling pathway, and reduced MMP9 overexpression induced by delayed rtPA thrombolysis. Conclusions. EA potentially represents an effective adjunct method to increase the safety of thrombolytic therapy and extend the therapeutic time window of rtPA administration following ischemic stroke. This neuroprotective effect may be mediated by the inhibition of the ERK1/2-MMP9 pathway and alleviation of the destruction of the BBB.