Combination treatment of r-tPA and an optimized human apyrase reduces mortality rate and hemorrhagic transformation 6h after ischemic stroke in aged female rats

Recombinant human soluble domain of CD39L3 and ticagrelor: cardioprotective effects in experimental myocardial infarction

BACKGROUND AND AIMS

The ecto-nucleoside triphosphate diphosphohydrolases of the CD39 family degrade ATP and ADP into AMP, which is converted into adenosine by the extracellular CD73/ecto-5-nucleotidase. This pathway has been explored in antithrombotic treatments but little in myocardial protection. We have investigated whether the administration of solCD39L3 (AZD3366) confers additional cardioprotection to that of ticagrelor alone in a pre-clinical model of myocardial infarction (MI).

METHODS

Ticagrelor-treated pigs underwent balloon-induced MI (90 min) and, before reperfusion, received intravenously either vehicle, 1 mg/kg AZD3366 or 3 mg/kg AZD3366. All animals received ticagrelor twice daily for 42 days. A non-treated MI group was run as a control. Serial cardiac magnetic resonance (baseline, Day 3 and Day 42 post-MI), light transmittance aggregometry, bleeding time, and histological and molecular analyses were performed.

RESULTS

Ticagrelor reduced oedema formation and infarct size at Day 3 post-MI vs. controls. A 3 mg/kg AZD3366 provided an additional 45% reduction in oedema and infarct size compared with ticagrelor and a 70% reduction vs. controls (P < .05). At Day 42, infarct size declined in all ticagrelor-administered pigs, particularly in 3 mg/kg AZD3366-treated pigs (P < .05). Left ventricular ejection fraction was diminished at Day 3 in placebo pigs and worsened at Day 42, whereas it remained unaltered in ticagrelor ± AZD3366-administered animals. Pigs administered with 3 mg/kg AZD3366 displayed higher left ventricular ejection fraction upon dobutamine stress at Day 3 and minimal dysfunctional segmental contraction at Day 42 (χ2P < .05 vs. all). Cardiac and systemic molecular readouts supported these benefits. Interestingly, AZD3366 abolished ADP-induced light transmittance aggregometry without affecting bleeding time.

CONCLUSIONS

Infusion of AZD3366 on top of ticagrelor leads to enhanced cardioprotection compared with ticagrelor alone.

Mechanical thrombectomy in patients with acute ischemic stroke in the USA before and after time window expansion

BACKGROUND

In 2018, the time window for mechanical thrombectomy eligibility in patients with acute ischemic stroke increased from within 6 hours to within 24 hours of symptom onset. The purpose of this study was to evaluate the effect of window expansion on procedural and hospital volumes and patient outcomes at a national level.

METHODS

We conducted a retrospective cohort study of patients with acute ischemic stroke undergoing mechanical thrombectomy using data from the National Inpatient Sample. We compared the numbers of mechanical thrombectomy procedures and performing hospitals between 2017 and 2019 in the USA, and the proportion of patients discharged home/self-care, those with in-hospital mortality and post-procedural intracranial hemorrhage (2019 vs 2017) after adjustment for potential confounders.

RESULTS

The number of patients with ischemic stroke who underwent mechanical thrombectomy increased from 16 960 in 2017 to 28 120 in 2019. There was an increase in the number of hospitals performing mechanical thrombectomy (501 in 2017, 585 in 2019) and those performing ≥50 procedures/year (97 in 2017, 199 in 2019; P<0.001). The odds of in-hospital mortality decreased (OR 0.79, 95% CI 0.66 to 0.94, P=0.008) and the odds of intracranial hemorrhage increased (OR 1.18, 95% CI 1.06 to 1.31, P=0.003) in 2019 compared with 2017, with no change in odds of discharge to home.

CONCLUSIONS

The window expansion for mechanical thrombectomy for patients with acute ischemic stroke was associated with an increase in the numbers of mechanical thrombectomy procedures and performing hospitals with a reduction of in-hospital mortality in the USA.

Protective effects of a novel glycogen phosphorylase inhibitor against cerebral ischemia-reperfusion injury in mice

Aim: To evaluate the effects of a novel glycogen phosphorylase inhibitor (NGPI) on cerebral ischemia-reperfusion injury (CIRI). Methods: Cerebral ischemia was induced in mice using a modified bilateral common carotid artery ligation model. To assess the effects of NGPI against CIRI, mice which had been administered with different doses of NGPI (1.25, 2.5, 5 mg/kg/day) for 7 days before the injury were evaluated for infarct volume, the apoptosis level of brain tissue, integrity of brain tissue and oxidative stress level. Results: NGPI effectively improved the infarct area, apoptosis of neurons, integrity of brain tissue and oxidative stress level of mice with CIRI. Conclusion: NGPI could effectively improve CIRI and deserves further study.

Role of Purinergic Signalling in Endothelial Dysfunction and Thrombo-Inflammation in Ischaemic Stroke and Cerebral Small Vessel Disease

The cerebral endothelium is an active interface between blood and the central nervous system. In addition to being a physical barrier between the blood and the brain, the endothelium also actively regulates metabolic homeostasis, vascular tone and permeability, coagulation, and movement of immune cells. Being part of the blood–brain barrier, endothelial cells of the brain have specialized morphology, physiology, and phenotypes due to their unique microenvironment. Known cardiovascular risk factors facilitate cerebral endothelial dysfunction, leading to impaired vasodilation, an aggravated inflammatory response, as well as increased oxidative stress and vascular proliferation. This culminates in the thrombo-inflammatory response, an underlying cause of ischemic stroke and cerebral small vessel disease (CSVD). These events are further exacerbated when blood flow is returned to the brain after a period of ischemia, a phenomenon termed ischemia-reperfusion injury. Purinergic signaling is an endogenous molecular pathway in which the enzymes CD39 and CD73 catabolize extracellular adenosine triphosphate (eATP) to adenosine. After ischemia and CSVD, eATP is released from dying neurons as a damage molecule, triggering thrombosis and inflammation. In contrast, adenosine is anti-thrombotic, protects against oxidative stress, and suppresses the immune response. Evidently, therapies that promote adenosine generation or boost CD39 activity at the site of endothelial injury have promising benefits in the context of atherothrombotic stroke and can be extended to current CSVD known pathomechanisms. Here, we have reviewed the rationale and benefits of CD39 and CD39 therapies to treat endothelial dysfunction in the brain.

The conditioned medium of human embryonic stem cell-derived mesenchymal stem cells alleviates neurological deficits and improves synaptic recovery in experimental stroke

The transplantation of mesenchymal stem cells (MSCs) is of main approaches in regenerative therapy for stroke. Due to the potential tumorigenicity and low survival rate of transplanted cells, focuses have been shifted from cell replacement to their paracrine effects. Therefore, stem cell-conditioned medium (CM) therapy has emerged as an alternative candidate. Here, we investigated the effect of CM derived from human embryonic MSCs on experimental ischemic stroke. Wistar rats underwent ischemic stroke by the right middle cerebral artery occlusion (MCAO). CM was infused either one time (1 hr post-MCAO) or three times (1, 24, and 48 hr post-MCAO) through guide cannula into the left lateral ventricle. Neurological functions were evaluated using Bederson's test and modified Neurological Severity Score on Days 1, 3, and 7 following MCAO. Infarction volumes and cerebral edema were measured on Days 3 and 7. growth-associated protein-43, synaptophysin, cAMP response element-binding protein, and phosphorylated-cAMP response element-binding protein levels were also assessed in peri-ischemic cortical tissue on Day 7 postsurgery. Our results indicated that three times injections of CM could significantly reduce body weight loss, mortality rate, infarct volumes, cerebral edema, and improve neurological deficits in MCAO rats. Moreover, three injections of CM could restore decreased levels of synaptic markers in MCAO rats up to its normal levels observed in the sham group. Our data suggest that using the CM obtained from embryonic stem cells-MSCs could be a potent therapeutic approach to attenuate cerebral ischemia insults which may be partly mediated through modulation of synaptic plasticity.

Human Recombinant Apyrase Therapy Protects Against Myocardial Ischemia/Reperfusion Injury and Preserves Left Ventricular Systolic Function in Rats, as Evaluated by 7T Cardiovascular Magnetic Resonance Imaging

OBJECTIVE

The occurrence of intramyocardial hemorrhage (IMH) and microvascular obstruction (MVO) in myocardial infarction (MI), known as severe ischemia/reperfusion injury (IRI), has been associated with adverse remodeling. APT102, a soluble human recombinant ecto-nucleoside triphosphate diphosphohydrolase-1, can hydrolyze extracellular nucleotides to attenuate their prothrombotic and proinflammatory effects. The purpose of this study was to temporally evaluate the therapeutic effect of APT102 on IRI in rats and to elucidate the evolution of IRI in the acute stage using cardiovascular magnetic resonance imaging (CMRI).

MATERIALS AND METHODS

Fifty-four rats with MI, induced by ligation of the origin of the left anterior descending coronary artery for 60 minutes, were randomly divided into the APT102 (n = 27) or control (n = 27) group. Intravenous infusion of APT102 (0.3 mg/kg) or placebo was administered 15 minutes before reperfusion, and then 24 hours, 48 hours, 72 hours, and on day 4 after reperfusion. CMRI was performed at 24 hours, 48 hours, 72 hours, and on day 5 post-reperfusion using a 7T system and the hearts were collected for histopathological examination. Cardiac function was quantified using cine imaging and IMH/edema using T2 mapping, and infarct/MVO using late gadolinium enhancement.

RESULTS

The extent of infarction (p < 0.001), edema (p < 0.001), IMH (p = 0.013), and MVO (p = 0.049) was less severe in the APT102 group than in the control group. IMH size at 48 hours was significantly greater than that at 24 hours, 72 hours, and 5 days after reperfusion (all p < 0.001). The left ventricular ejection fraction (LVEF) was significantly greater in the APT102 group than in the control group (p = 0.006). There was a negative correlation between LVEF and IMH (r = -0.294, p = 0.010) and a positive correlation between IMH and MVO (r = 0.392, p < 0.001).

CONCLUSION

APT102 can significantly alleviate damage to the ischemic myocardium and microvasculature. IMH size peaked at 48 hours post reperfusion and IMH is a downstream consequence of MVO. IMH may be a potential therapeutic target to prevent adverse remodeling in MI.

The role of non-coding RNAs in neuroprotection and angiogenesis following ischemic stroke

Stroke is the leading cause of death and physical disability worldwide. Non-coding RNAs (ncRNAs) are endogenous molecules that play key roles in the pathophysiology and retrieval processes following ischemic stroke. The potential of ncRNAs, especially microRNAs (miRNAs) and long non-coding RNAs (lncRNAs) in neuroprotection and angiogenesis highlights their potential as targets for therapeutic intervention. In this review, we document the miRNAs and lncRNAs that have been reported to exert regulatory actions in neuroprotective and angiogenic processes through different mechanisms involving their interaction with target coding genes. We believe that exploration of the expression profiles and the possible functions of ncRNAs during the recovery processes will help comprehension of the molecular mechanisms responsible for neuroprotection and angiogenesis, and may also contribute to find biomarkers and targets for future stroke intervention.

Long non-coding RNAs and cell death following ischemic stroke

Stroke is a major cause of morbidity and mortality worldwide, and extensive efforts have focused on the improvement of therapeutic strategies to reduce cell death following ischemic stroke. Uncovering the cellular and molecular pathophysiological processes in ischemic stroke have been a top priority. Long noncoding RNAs (lncRNAs) are endogenous molecules that play key roles in the pathophysiology of cerebral ischemia, and involved in the neuronal cell death during ischemic stroke. In recent years, a bulk of aberrantly expressed lncRNAs have been screened out in ischemic stroke insulted animals. LncRNAs along with their targets could affect the genetic machinery at molecular levels, and exploring their functions and mechanisms may be a promising option for ischemic stroke treatment. In this review, we summarize the current knowledge for lncRNAs in ischemic stroke, focusing on the role of specific lncRNAs that may underlie cell death to find possible therapeutic targets.

Gastrodin Inhibits Inflammasome Through the STAT3 Signal Pathways in TNA2 Astrocytes and Reactive Astrocytes in Experimentally Induced Cerebral Ischemia in Rats

This study was aimed to determine Gastrodin (GAS) and its underlying signaling pathway involved in suppression of inflammasome specifically in reactive astrocytes that are featured prominently in different neurological conditions or diseases including cerebral ischemia. For this purpose, TNA2 astrocytes in cultures were exposed to oxygen-glucose-deprivation (OGD) mimicking hypoxic cerebral ischemia. Separately, TNA2 cells were pretreated with GAS prior to OGD exposure. Additionally, Stattic, an inhibitor of STAT3 signaling pathway, was used to ascertain its involvement in regulating inflammasome in astrocytes exposed to OGD. In parallel to the above, adult rats subjected to middle cerebral artery occlusion (MCAO) with or without GAS pretreatment were sacrificed at different time points to determine the effects of GAS on astrocyte inflammasome. TNA2 astrocytes in different treatments as well as reactive astrocytes in MCAO were processed for immunofluorescence labeling and Western blot analysis for various protein markers. In the latter, protein expression levels of p-STAT3, NLRP3, and NLRC4 were markedly increased in TNA2 astrocytes exposed to OGD. Remarkably, the expression levels of these biomarkers were significantly suppressed by GAS. Of note, GAS especially at dose 20 μM inhibited NLRP3 and NLRC4 expression levels most substantially. Moreover, GAS inhibited the downstream proteins caspase-1 and IL-18. Concomitantly, GAS significantly suppressed the expression of STAT3 and NF-κB signaling pathway. It is noteworthy that Stattic at dose 100 μM inhibited STAT3 pathway and NF-κB activation in TNA2 astrocytes, an effect that was shared by GAS. In MCAO, GAS was found to effectively attenuate p-STAT3 immunofluorescence intensity in reactive astrocytes. Arising from the above, it is concluded that GAS is anti-inflammatory as it effectively suppresses inflammasome in OGD-stimulated astrocytes as well as in reactive astrocytes in MCAO via STAT3 and NF-κB signaling expression coupled with decreased expression of caspase-1 and IL-18.

Gastrodin improves the neurological score in MCAO rats by inhibiting inflammation and apoptosis, promoting revascularization

Gastrodin (GAS) is an active constituent of Chinese herbal medicine tianma (Gastrodia elata), which is commonly used to extinguish wind (TCM term). Tianma is also widely used to treat various neurological diseases such as stroke, dizziness, epilepsy, etc. Its clinical effect is quite satisfactory. However, the underlying mechanism has not been fully explored. In the present study, we choose a permanent cerebral occlusion model, MCAO, and used multiple methods to investigate the medicine. Our results show a significant improvement in neurological score after 3 days of GAS treatment. In addition, neurons in the hippocampus were rescued within after 7 days GAS treatment. Then we explore the drug's mechanism in the acute phase of stroke. CRP and IL-1β are common inflammatory factors. Elisa showed GAS can reduce these inflammatory factors in serum in the acute phase of stroke. What's more, GAS can up-regulate the expression of Bcl-2 and down-regulate the expression of BAX in the ischemic hemisphere, and the same result is observed in the protein level. The expression of Caspase-3 is also suppressed, indicating GAS has ability to inhibit apoptosis during the acute phase of stroke. On the other hand, GAS can up-regulate the expression of VEGF, thusly promoting micro-vacsular regeneration. In conclusion, our results demonstrate that GAS can alleviate the symptoms of stroke through various mechanisms. GAS might also serve as a potential candidate to treat acute cerebral infarction.

Pharmacological approaches promoting stem cell-based therapy following ischemic stroke insults

Stroke can lead to long-term neurological deficits. Adult neurogenesis, the continuous generation of newborn neurons in distinct regions of the brain throughout life, has been considered as one of the appoaches to restore the neurological function following ischemic stroke. However, ischemia-induced spontaneous neurogenesis is not suffcient, thus cell-based therapy, including infusing exogenous stem cells or stimulating endogenous stem cells to help repair of injured brain, has been studied in numerous animal experiments and some pilot clinical trials. While the effects of cell-based therapy on neurological function during recovery remains unproven in randomized controlled trials, pharmacological agents have been administrated to assist the cell-based therapy. In this review, we summarized the limitations of ischemia-induced neurogenesis and stem-cell transplantation, as well as the potential proneuroregenerative effects of drugs that may enhance efficacy of cell-based therapies. Specifically, we discussed drugs that enhance proliferation, migration, differentiation, survival and function connectivity of newborn neurons, which may restore neurobehavioral function and improve outcomes in stroke patients.

Role of Transporters in Central Nervous System Drug Delivery and Blood-Brain Barrier Protection: Relevance to Treatment of Stroke

Ischemic stroke is a leading cause of morbidity and mortality in the United States. The only approved pharmacologic treatment for ischemic stroke is thrombolysis via recombinant tissue plasminogen activator (r-tPA). A short therapeutic window and serious adverse events (ie, hemorrhage, excitotoxicity) greatly limit r-tPA therapy, which indicates an essential need to develop novel stroke treatment paradigms. Transporters expressed at the blood-brain barrier (BBB) provide a significant opportunity to advance stroke therapy via central nervous system delivery of drugs that have neuroprotective properties. Examples of such transporters include organic anion–transporting polypeptides (Oatps) and organic cation transporters (Octs). In addition, multidrug resistance proteins (Mrps) are transporter targets in brain microvascular endothelial cells that can be exploited to preserve BBB integrity in the setting of stroke. Here, we review current knowledge on stroke pharmacotherapy and demonstrate how endogenous BBB transporters can be targeted for improvement of ischemic stroke treatment.

Recombinant soluble apyrase APT102 inhibits thrombosis and intimal hyperplasia in vein grafts without adversely affecting hemostasis or re-endothelialization

Essentials New strategies are needed to inhibit thrombosis and intimal hyperplasia (IH) in vein grafts (VG). We studied effects of apyrase (APT102) on VGs and smooth muscle and endothelial cells (SMC/EC). APT102 inhibited thrombosis, SMC migration, and IH without impairing hemostasis or EC recovery. Apyrase APT102 is a single-drug approach to inhibit multiple processes that cause VG failure.

SUMMARY

Background Occlusion of vein grafts (VGs) after bypass surgery, owing to thrombosis and intimal hyperplasia (IH), is a major clinical problem. Apyrases are enzymes that scavenge extracellular ATP and ADP, and promote adenosine formation at sites of vascular injury, and hence have the potential to inhibit VG pathology. Objectives To examine the effects of recombinant soluble human apyrase, APT102, on platelets, smooth muscle cells (SMCs) and endothelial cells (ECs) in vitro, and on thrombosis and IH in murine VGs. Methods SMC and EC proliferation and migration were studied in vitro. Inferior vena cava segments from donor mice were grafted into carotid arteries of recipient mice. Results APT102 potently inhibited ADP-induced platelet aggregation and VG thrombosis, but it did not impair surgical hemostasis. APT102 did not directly inhibit SMC or EC proliferation, but significantly attenuated the effects of ATP on SMC and EC proliferation. APT102 significantly inhibited SMC migration, but did not inhibit EC migration, which may be mediated, at least in part, by inhibition of SMC, but not EC, migration by adenosine. At 4 weeks after surgery, there was significantly less IH in VGs of APT102-treated mice than in control VGs. APT102 significantly inhibited cell proliferation in VGs, but did not inhibit re-endothelialization. Conclusions Systemic administration of a recombinant human apyrase inhibits thrombosis and IH in VGs without increasing bleeding or compromising re-endothelialization. These results suggest that APT102 has the potential to become a novel, single-drug treatment strategy to prevent multiple pathologic processes that drive early adverse remodeling and occlusion of VGs.

Electroacupuncture Attenuates Cerebral Ischemia and Reperfusion Injury in Middle Cerebral Artery Occlusion of Rat via Modulation of Apoptosis, Inflammation, Oxidative Stress, and Excitotoxicity

Electroacupuncture (EA) has several properties such as antioxidant, antiapoptosis, and anti-inflammatory properties. The current study was to investigate the effects of EA on the prevention and treatment of cerebral ischemia-reperfusion (I/R) injury and to elucidate possible molecular mechanisms. Sprague-Dawley rats were subjected to middle cerebral artery occlusion (MCAO) for 2 h followed by reperfusion for 24 h. EA stimulation was applied to both Baihui and Dazhui acupoints for 30 min in each rat per day for 5 successive days before MCAO (pretreatment) or when the reperfusion was initiated (treatment). Neurologic deficit scores, infarction volumes, brain water content, and neuronal apoptosis were evaluated. The expressions of related inflammatory cytokines, apoptotic molecules, antioxidant systems, and excitotoxic receptors in the brain were also investigated. Results showed that both EA pretreatment and treatment significantly reduced infarct volumes, decreased brain water content, and alleviated neuronal injury in MCAO rats. Notably, EA exerts neuroprotection against I/R injury through improving neurological function, attenuating the inflammation cytokines, upregulating antioxidant systems, and reducing the excitotoxicity. This study provides a better understanding of the molecular mechanism underlying the traditional use of EA.

GSK-3β inhibitor TWS119 attenuates rtPA-induced hemorrhagic transformation and activates the Wnt/β-catenin signaling pathway after acute ischemic stroke in rats

Hemorrhagic transformation (HT) is a devastating complication for patients with acute ischemic stroke who are treated with tissue plasminogen activator (tPA). It is associated with high morbidity and mortality, but no effective treatments are currently available to reduce HT risk. Therefore, methods to prevent HT are urgently needed. In this study, we used TWS119, an inhibitor of glycogen synthase kinase 3β (GSK-3β), to evaluate the role of the Wnt/β-catenin signaling pathway in recombinant tPA (rtPA)-induced HT. Sprague-Dawley rats were subjected to a middle cerebral artery occlusion (MCAO) model of ischemic stroke and then were administered rtPA, rtPA combined with TWS119, or vehicle at 4 h. The animals were sacrificed 24 h after infarct induction. Rats treated with rtPA showed evident HT, had more severe neurologic deficit, brain edema, and blood-brain barrier breakdown, and had larger infarction volume than did the vehicle group. Rats treated with TWS119 had significantly improved outcomes compared with those of rats treated with rtPA alone. In addition, Western blot analysis showed that TWS119 increased the protein expression of β-catenin, claudin-3, and ZO-1 while suppressing the expression of GSK-3β. These results suggest that TWS119 reduces rtPA-induced HT and attenuates blood-brain barrier disruption, possibly through activation of the Wnt/β-catenin signaling pathway. This study provides a potential therapeutic strategy to prevent tPA-induced HT after acute ischemic stroke.

Docosahexaenoic acid attenuates hyperglycemia-enhanced hemorrhagic transformation after transient focal cerebral ischemia in rats

Hemorrhagic transformation (HT) is a feared complication of cerebral ischemic infarction, especially following the use of thrombolytic therapy. In this study, we examined whether docosahexaenoic acid (DHA; 22:6n-3), an omega-3 essential fatty acid family member, can protect the brain from injury and whether DHA can decrease the risk of HT enhanced by hyperglycemia after focal ischemic injury. Male Sprague-Dawley rats were injected with 50% dextrose (6ml/kg intraperitoneally) to induce hyperglycemia 10min before 1.5h of filament middle cerebral artery occlusion (MCAO) was performed. Treatment with DHA (10mg/kg) 5min before reperfusion reduced HT and further improved the 7-day neurological outcome. It also reduced infarct volume, which is consistent with the restricted DWI and T2WI hyperintensive area. Reduced Evans Blue extravasation and increased expression of collagen IV indicated the improved integrity of the blood-brain barrier (BBB) in DHA-treated rats. Moreover, DHA reduced the expression of the intercellular adhesion molecule-1 (ICAM-1) in the ischemic injured brain. Therefore, we conclude that DHA attenuated hyperglycemia-enhanced HT and improved neurological function by preserving the integrity of BBB and reducing inflammation.