Neuroprotective agents in Acute Ischemic Stroke-A Reality Check

Salidroside derivative SHPL-49 attenuates glutamate excitotoxicity in acute ischemic stroke via promoting NR2A-CAMKⅡα-Akt /CREB pathway

BACKGROUND

Ischemic stroke is a significant cause of death and disability with a limited treatment time window. The reduction of early glutamate excitotoxicity using neuroprotective agents targeting N-methyl-d-aspartic acid (NMDA) receptors have attracted recent research attention. SHPL-49, a structurally modified derivative of salidroside, was synthesized by our team. Previous studies have confirmed the neuroprotective efficacy of SHPL-49 in rats with ischemic stroke. However, the underlying mechanisms need to be clarified.

METHODS

We conducted in vivo experiments using the permanent middle cerebral artery occlusion rat model to investigate the role of SHPL-49 in glutamate release at different time points and treatment durations. Glutamate transporters and receptor proteins and neural survival proteins in the brain were also examined at the same time points. In vitro, primary neurons and the coculture system of primary neurons-astrocytes were subjected to oxygen-glucose deprivation and glutamate injury. Proteomics and parallel reaction monitoring analyses were performed to identify potential therapeutic targets of SHPL-49, which were further confirmed through in vitro experiments on the inhibition and mutation of the target.

RESULTS

SHPL-49 significantly reduced glutamate release caused by hypoxia-ischemia. One therapeutic pathway of SHPL-49 was promoting the expression of glutamate transporter-1 to increase glutamate reuptake and further reduce the occurrence of subsequent neurotoxicity. In addition, we explored the therapeutic targets of SHPL-49 and its regulatory effects on glutamate receptors for the first time. SHPL-49 enhanced neuroprotection by activating the NMDA subunit NR2A, which upregulated the cyclic-AMP response binding protein (CREB) neural survival pathway and Akt phosphorylation. Since calcium/calmodulin-dependent kinase IIα (CaMKIIα) is necessary for synaptic transmission of NMDA receptors, we explored the interaction between CaMKIIα and SHPL-49, which protected CaMKIIα from hypoxia-ischemia-induced autophosphorylation damage.

CONCLUSION

Overall, SHPL-49 enhanced neuronal survival and attenuated acute ischemic stroke by promoting the NR2A-CAMKⅡα-Akt/CREB pathway. Our study provides the first evidence demonstrating that the neuroprotective effect of SHPL-49 is achieved by promoting the NR2A subunit to extend the treatment time window, making it a promising drug for ischemic stroke.

Updated evidence of the Naoshuantong capsule against ischemic stroke: a systematic review and meta-analysis of randomized controlled trials

Background

Stroke is a serious health issue that can result in death or disability, leading to a significant economic strain on society and families. A growing number of studies have shown that the Naoshuantong capsule (NSTC) is beneficial as a treatment for ischemic stroke (IS) in recent years. Our study aims to provide an update on the safety and efficacy of the NSTC in IS patients.

Methods

We thoroughly searched eight databases to identify suitable randomized controlled trials (RCTs) assessing the effectiveness of the NSTC in the treatment of IS. The National Institute of Health Stroke Scale (NIHSS) for an acute period and modified Rankin Scale (mRS) at 3 months for a non-acute period were considered the primary outcome, and secondary outcomes included the NIHSS for a non-acute period, mRS, Barthel Index (BI), modified Barthel Index (MBI), Stroke-specific Quality of life (SS-QOL), and the recurrence rate of cerebrovascular events. Subsequently, its quality was assessed using the Cochrane risk assessment scale. Statistical analysis was conducted using RevMan 5.3 and Stata 14.0.

Results

A total of 27 RCTs were included, which involved 3,139 patients. The results showed that the NSTC improved neurological function not only in the acute period (MD = -2.53; 95% CI: -2.91, -2.15; p < 0.00001) but also in the non-acute period (MD = -3.70; 95% CI: -5.82, -1.58; p = 0.0006) and improved the long-term functional outcomes with lower mRS scores (MD = -0.68; 95% CI: -1.09, -0.26; p = 0.001). At the same time, the NSTC decreased the risk of cerebrovascular disease recurrence (RR = 0.43; 95% CI: 0.27, 0.70; p = 0.0006) and increased the quality of life in the acute period (MD = 23.88; 95% CI: 16.63, 31.13; p < 0.00001). Significant disparities in the incidence of adverse events between the NSTC and control groups were not observed. The certainty of evidence was estimated as moderate to very low.

Conclusion

The NSTC emerges as a potentially efficacious and safe treatment option for IS. NSTC could improve neurological function in different period of IS, and it has certain clinical value in secondary prevention. As a result of the poor quality and heterogeneity of the included trials, larger and standardized RCTs are needed to validate NSTC in IS treatment.

Systematic Review Registration

https://www.crd.york.ac.uk/PROSPERO/display_record.php?RecordID=482981, identifier CRD42023482981.

Exploring the anti-ischemic stroke potential of wogonoside: Insights from Nrf2/Sirt3 signaling pathway and UPLC-TripleTOF-MS/MS-based metabolomics

Ischemic stroke, accounting for 80 % of all strokes, is a major cause of morbidity and mortality worldwide. However, effective and safe pharmacotherapy options for ischemic injury are limited. This study investigated the therapeutic effects of wogonoside, a compound derived from Radix Scutellariae, on ischemia/reperfusion (I/R) injury. The results showed that wogonoside treatment had significant therapeutic effects in rats with middle cerebral artery occlusion. It effectively reduced mortality rates, neurological deficits, cerebral infarct size, and brain water content. In an in vitro model using PC12 cells, wogonoside activated the Nrf2/Sirt3 signaling pathway. This activation contributed to the attenuation of oxidative damage and inflammation. Metabolomics analysis revealed increased levels of γ-aminobutyric acid (GABA) and glutathione in response to wogonoside treatment, suggesting their potential as therapeutic biomarkers for ischemic stroke. Additionally, wogonoside restored perturbed energy metabolism, including the tricarboxylic acid cycle. Wogonoside has the potential to ameliorate cerebral ischemic injury by targeting GABA-related amino acid metabolism, energy metabolism, and glutathione metabolism, maintaining redox homeostasis, and attenuating oxidative stress. These findings provide valuable insights into the protective mechanisms of wogonoside in cerebral I/R injury and highlight the promising therapeutic approach of wogonoside in the treatment of ischemic stroke.

Application of targeted liposomes-based salvianolic acid A for the treatment of ischemic stroke

Novel therapeutics for the treatment of ischemic stroke remains to be the unmet clinical needs. Previous studies have indicated that salvianolic acid A (SAA) is a promising candidate for the treatment of the brain diseases. However, SAA has poor absolute bioavailability and does not efficiently cross the intact blood-brain barrier (BBB), which limit its efficacy. To this end we developed a brain-targeted liposomes for transporting SAA via the BBB by incorporating the liposomes to a transport receptor, insulin-like growth factor-1 receptor (IGF1R). The liposomes were prepared by ammonium sulfate gradients loading method. The prepared SAA-loaded liposomes (Lipo/SAA) were modified with IGF1R monoclonal antibody to generate IGF1R antibody-conjugated Lipo/SAA (IGF1R-targeted Lipo/SAA). The penetration of IGF1R-targeted Lipo/SAA into the brain was confirmed by labeling with Texas Red, and their efficacy were evaluate using middle cerebral artery occlusion (MCAO) model. The results showed that IGF1R-targeted Lipo/SAA are capable of transporting SAA across the BBB into the brain, accumulation in brain tissue, and sustained releasing SAA for several hours. Administration o IGF1R-targeted Lipo/SAA notably reduced infarct size and neuronal damage, improved neurological function and inhibited cerebral inflammation, which had much higher efficiency than no-targeted SAA.

Cerebrolysin for acute ischaemic stroke

BACKGROUND

Cerebrolysin is a mixture of low-molecular-weight peptides and amino acids derived from porcine brain, which has potential neuroprotective properties. It is widely used in the treatment of acute ischaemic stroke in Russia, Eastern Europe, China, and other Asian and post-Soviet countries. This is an update of a review first published in 2010 and last updated in 2020.

OBJECTIVES

To assess the benefits and harms of Cerebrolysin or Cerebrolysin-like agents for treating acute ischaemic stroke.

SEARCH METHODS

We searched the Cochrane Stroke Trials Register, CENTRAL, MEDLINE, Embase, Web of Science Core Collection, with Science Citation Index, and LILACS in May 2022 and a number of Russian databases in June 2022. We also searched reference lists, ongoing trials registers, and conference proceedings.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing Cerebrolysin or Cerebrolysin-like agents started within 48 hours of stroke onset and continued for any length of time, with placebo or no treatment in people with acute ischaemic stroke.

DATA COLLECTION AND ANALYSIS

Three review authors independently applied the inclusion criteria, assessed trial quality and risk of bias, extracted data, and applied GRADE criteria to the evidence.

MAIN RESULTS

Seven RCTs (1773 participants) met the inclusion criteria of the review. In this update we added one RCT of Cerebrolysin-like agent Cortexin, which contributed 272 participants. We used the same approach for risk of bias assessment that was re-evaluated for the previous update: we added consideration of the public availability of study protocols and reported outcomes to the selective outcome reporting judgement, through identification, examination, and evaluation of study protocols. For the Cerebrolysin studies, we judged the risk of bias for selective outcome reporting to be unclear across all studies; for blinding of participants and personnel to be low in three studies and unclear in the remaining four; and for blinding of outcome assessors to be low in three studies and unclear in four studies. We judged the risk of bias for generation of allocation sequence to be low in one study and unclear in the remaining six studies; for allocation concealment to be low in one study and unclear in six studies; and for incomplete outcome data to be low in three studies and high in the remaining four studies. The manufacturer of Cerebrolysin supported three multicentre studies, either totally, or by providing Cerebrolysin and placebo, randomisation codes, research grants, or statisticians. We judged two studies to be at high risk of other bias and the remaining five studies to be at unclear risk of other bias. We judged the study of Cortexin to be at low risk of bias for incomplete outcome data and at unclear risk of bias for all other domains. All-cause death: Cerebrolysin or Cortexin probably result in little to no difference in all-cause death (risk ratio (RR) 0.96, 95% confidence interval (CI) 0.65 to 1.41; 6 trials, 1689 participants; moderate-certainty evidence). None of the included studies reported on poor functional outcome, defined as death or dependence at the end of the follow-up period, early death (within two weeks of stroke onset), quality of life, or time to restoration of capacity for work. Only one study clearly reported on the cause of death: cerebral infarct (four in the Cerebrolysin and two in the placebo group), heart failure (two in the Cerebrolysin and one in the placebo group), pulmonary embolism (two in the placebo group), and pneumonia (one in the placebo group). Non-death attrition (secondary outcome): Cerebrolysin or similar peptide mixtures may result in little to no difference in non-death attrition, but the evidence is very uncertain, with a considerable level of heterogeneity (RR 0.72, 95% CI 0.38 to 1.39; 6 trials, 1689 participants; very low-certainty evidence). Serious adverse events (SAEs): Cerebrolysin probably results in little to no difference in the total number of people with SAEs (RR 1.16, 95% CI 0.81 to 1.66; 3 trials, 1335 participants; moderate-certainty evidence). This comprised fatal SAEs (RR 0.90, 95% CI 0.59 to 1.38; 3 trials, 1335 participants; moderate-certainty evidence) and an increase in the total number of people with non-fatal SAEs (RR 2.39, 95% CI 1.10 to 5.23; 3 trials, 1335 participants; moderate-certainty evidence). In the subgroup of dosing schedule 30 mL for 10 days (cumulative dose 300 mL), the increase was more prominent (RR 2.87, 95% CI 1.24 to 6.69; 2 trials, 1189 participants). Total number of people with adverse events: Cerebrolysin or similar peptide mixtures may result in little to no difference in the total number of people with adverse events (RR 1.03, 95% CI 0.92 to 1.14; 4 trials, 1607 participants; low-certainty evidence).

AUTHORS' CONCLUSIONS

Moderate-certainty evidence indicates that Cerebrolysin or Cerebrolysin-like peptide mixtures derived from cattle brain probably have no beneficial effect on preventing all-cause death in acute ischaemic stroke. Moderate-certainty evidence suggests that Cerebrolysin probably has no beneficial effect on the total number of people with serious adverse events. Moderate-certainty evidence also indicates a potential increase in non-fatal serious adverse events with Cerebrolysin use.

Integrative Approaches in Acute Ischemic Stroke: From Symptom Recognition to Future Innovations

Among the high prevalence of cerebrovascular diseases nowadays, acute ischemic stroke stands out, representing a significant worldwide health issue with important socio-economic implications. Prompt diagnosis and intervention are important milestones for the management of this multifaceted pathology, making understanding the various stroke-onset symptoms crucial. A key role in acute ischemic stroke management is emphasizing the essential role of a multi-disciplinary team, therefore, increasing the efficiency of recognition and treatment. Neuroimaging and neuroradiology have evolved dramatically over the years, with multiple approaches that provide a higher understanding of the morphological aspects as well as timely recognition of cerebral artery occlusions for effective therapy planning. Regarding the treatment matter, the pharmacological approach, particularly fibrinolytic therapy, has its merits and challenges. Endovascular thrombectomy, a game-changer in stroke management, has witnessed significant advances, with technologies like stent retrievers and aspiration catheters playing pivotal roles. For select patients, combining pharmacological and endovascular strategies offers evidence-backed benefits. The aim of our comprehensive study on acute ischemic stroke is to efficiently compare the current therapies, recognize novel possibilities from the literature, and describe the state of the art in the interdisciplinary approach to acute ischemic stroke. As we aspire for holistic patient management, the emphasis is not just on medical intervention but also on physical therapy, mental health, and community engagement. The future holds promising innovations, with artificial intelligence poised to reshape stroke diagnostics and treatments. Bridging the gap between groundbreaking research and clinical practice remains a challenge, urging continuous collaboration and research.

Treatment of Stroke at a Delayed Timepoint with a Repurposed Drug Targeting Sigma 1 Receptors

Sigma 1 receptors are intracellular chaperone proteins that have been explored as a subacute treatment to enhance post-stroke recovery. We recently identified the antitussive oxeladin as a selective sigma 1 receptor agonist with the ability to stimulate the release of brain-derived neurotrophic factor from neurons in vitro. In this study, we hypothesized that oral oxeladin citrate would stimulate BDNF secretion and improve stroke outcomes when administered to male rats starting 48 h after transient middle cerebral artery occlusion. Oxeladin did not alter blood clotting and crossed the blood brain barrier within 30 min of oral administration. Rats underwent 90 min of transient middle cerebral artery occlusion. Forty-eight hours later rats began receiving daily oxeladin (135 mg/kg) for 11 days. Oxeladin significantly improved neurological function on days 3, 7, and 14 following MCAO. Infarct size was not altered by a single dose, but the final extent of infarct after 14 days was decreased. However, there was no significant reduction in astrogliosis or microgliosis compared to vehicle-treated control rats. In agreement with in vitro studies, oxeladin increased the amount of mature BDNF in the cerebral cortex 2, 6, and 24 h after single oral dose. However, the increase in BDNF did not result in increases in cellular proliferation in the subventricular zone or dentate gyrus when compared to vehicle-treated controls. These results suggest that oxeladin may reduce the extent of infarct expansion in the subacute phase of stroke, although this action does not appear to involve a reduction in inflammation or increased cell proliferation.

A feasibility and safety study of afamelanotide in acute stroke patients - an open label, proof of concept, phase iia clinical trial

BACKGROUND

Neuroprotective agents have the potential to improve the outcomes of revascularisation therapies in acute ischemic stroke patients (AIS) and in those unable to receive revascularisation. Afamelanotide, a synthetic α-melanocyte stimulating hormone analogue, is a potential novel neuroprotective agent. We set out to assess the feasibility and safety of afamelanotide for the first time in AIS patients.

METHODS

AIS patients within 24 h of onset, with perfusion abnormality on imaging (Tmax) and otherwise ineligible for revascularisation therapies were enrolled. Afamelanotide 16 mg implants were administered subcutaneously on Day 0 (D0, day of recruitment), D1 and repeated on D7 and D8, if not well recovered. Treatment emergent adverse events (TEAEs) and neurological assessments were recorded regularly up to D42. Magnetic resonance imaging (MRI) with FLAIR sequences were also performed on D3 and D9.

RESULTS

Six patients (5 women, median age 81, median NIHSS 6) were recruited. Two patients received 4 doses and four patients received 2. One patient (who received 2 doses), suffered a fatal recurrent stroke on D9 due to a known complete acute internal carotid artery occlusion, assessed as unrelated to the study drug. There were no other local or major systemic TEAEs recorded. In all surviving patients, the median NIHSS improved from 6 to 2 on D7. The median Tmax volume on D0 was 23 mL which was reduced to a FLAIR volume of 10 mL on D3 and 4 mL on D9.

CONCLUSIONS

Afamelanotide was well tolerated and safe in our small sample of AIS patients. It also appears to be associated with good recovery and radiological improvement of salvageable tissue which needs to be tested in randomized studies.

CLINICALTRIALS

GOV IDENTIFIER

NCT04962503, First posted 15/07/2021.

Neuroprotective and Antioxidant Properties of CholesteroNitrone ChN2 and QuinolylNitrone QN23 in an Experimental Model of Cerebral Ischemia: Involvement of Necrotic and Apoptotic Cell Death

Ischemic stroke is the leading cause of disability and the second leading cause of death worldwide. However, current therapeutic strategies are scarce and of limited efficacy. The abundance of information available on the molecular pathophysiology of ischemic stroke has sparked considerable interest in developing new neuroprotective agents that can target different events of the ischemic cascade and may be used in combination with existing treatments. In this regard, nitrones represent a very promising alternative due to their renowned antioxidant and anti-inflammatory effects. In this study, we aimed to further investigate the neuroprotective effects of two nitrones, cholesteronitrone 2 (ChN2) and quinolylnitrone 23 (QN23), which have previously shown great potential for the treatment of stroke. Using an experimental in vitro model of cerebral ischemia, we compared their anti-necrotic, anti-apoptotic, and antioxidant properties with those of three reference compounds. Both ChN2 and QN23 demonstrated significant neuroprotective effects (EC₅₀ = 0.66 ± 0.23 μM and EC₅₀ = 2.13 ± 0.47 μM, respectively) comparable to those of homo-bis-nitrone 6 (HBN6) and N-acetylcysteine (NAC) and superior to those of α-phenyl-N-tert-butylnitrone (PBN). While primarily derived from the nitrones' anti-necrotic capacities, their anti-apoptotic effects at high concentrations and antioxidant powers-especially in the case of QN23-also contribute to their neuroprotective effects.

Influence of sex, age and diabetes on brain transcriptome and proteome modifications following cerebral ischemia

Ischemic stroke is a major cause of death and disability worldwide. Translation into the clinical setting of neuroprotective agents showing promising results in pre-clinical studies has systematically failed. One possible explanation is that the animal models used to test neuroprotectants do not properly represent the population affected by stroke, as most of the pre-clinical studies are performed in healthy young male mice. Therefore, we aimed to determine if the response to cerebral ischemia differed depending on age, sex and the presence of comorbidities. Thus, we explored proteomic and transcriptomic changes triggered during the hyperacute phase of cerebral ischemia (by transient intraluminal middle cerebral artery occlusion) in the brain of: (1) young male mice, (2) young female mice, (3) aged male mice and (4) diabetic young male mice. Moreover, we compared each group's proteomic and transcriptomic changes using an integrative enrichment pathways analysis to disclose key common and exclusive altered proteins, genes and pathways in the first stages of the disease. We found 61 differentially expressed genes (DEG) in male mice, 77 in females, 699 in diabetics and 24 in aged mice. Of these, only 14 were commonly dysregulated in all groups. The enrichment pathways analysis revealed that the inflammatory response was the biological process with more DEG in all groups, followed by hemopoiesis. Our findings indicate that the response to cerebral ischemia regarding proteomic and transcriptomic changes differs depending on sex, age and comorbidities, highlighting the importance of incorporating animals with different phenotypes in future stroke research studies.

Neuroprotective potential of lignan-rich fraction of Piper cubeba L. by improving antioxidant capacity in the rat's brain

Piper cubeba contains various types of lignans. These compounds have been found to have potential pharmacological activities, one being a neuroprotector through an antioxidant mechanism, especially in the brain. This study examined the antioxidant activity of the lignan-rich fraction of P. cubeba (LF) in rat brains. The rats were given LF (200 and 400 mg/kg), Vitamin C (200 mg/kg), and a carrier as the control group for one-week p.o. The following day, rat brains were collected for antioxidant tests, including examining lipid peroxide inhibition, superoxide dismutase and catalase activity, and determination of nitric oxide (NO) concentration. The phytochemical compounds were analyzed with thin-layer chromatography (TLC), ultra-high performance liquid chromatography-tandem mass spectrometry (UPLC-MS), and gas chromatography-mass spectrometry (GC-MS). Test results show that the LF of both doses of 200 and 400 mg/kg could significantly increase antioxidant activity in the brain by inhibiting lipid peroxidation. LF could also increase catalase, despite the decrease in superoxide dismutase activity. Reduction in NO only occurred in the LF-200 group, while LF-400 showed insignificant results compared to the control group. In conclusion, LF showed potential as an antioxidant in the brain and could be beneficial for treating neurological diseases.

Neuroprotective approach in acute ischemic stroke: A systematic review of clinical and experimental studies

Ischemic stroke is a disease with worldwide economic and social negative effects. It is a serious disease with high disability and mortality. Ionic imbalance, excitotoxicity, oxidative stress, and inflammation are induced during and after ischemic stroke. Cellular dysfunction, apoptosis, and necrosis are activated directly or indirectly mechanisms. The studies about neuroprotection in neurodegenerative diseases have increased in recent years. Data about the mechanisms of progressive molecular improvement in the brain tissue are increasing in acute ischemic stroke. Based on these data, preclinical and clinical studies on new neuroprotective treatments are being designed. An effective neuroprotective strategy can prolong the indication period of recanalization treatments in the acute stage of ischemic stroke. In addition, it can reduce neuronal necrosis and protect the brain against ischemia-related reperfusion injury. The current review has evaluated the recent clinical and experimental studies. The molecular mechanism of each of the neuroprotective strategies is also summarized. This review may help develop future strategies for combination treatment to protect the cerebral tissue from ischemia-reperfusion injury.

Excitatory Synaptic Transmission in Ischemic Stroke: A New Outlet for Classical Neuroprotective Strategies

Stroke is one of the leading causes of death and disability in the world, of which ischemia accounts for the majority. There is growing evidence of changes in synaptic connections and neural network functions in the brain of stroke patients. Currently, the studies on these neurobiological alterations mainly focus on the principle of glutamate excitotoxicity, and the corresponding neuroprotective strategies are limited to blocking the overactivation of ionic glutamate receptors. Nevertheless, it is disappointing that these treatments often fail because of the unspecificity and serious side effects of the tested drugs in clinical trials. Thus, in the prevention and treatment of stroke, finding and developing new targets of neuroprotective intervention is still the focus and goal of research in this field. In this review, we focus on the whole processes of glutamatergic synaptic transmission and highlight the pathological changes underlying each link to help develop potential therapeutic strategies for ischemic brain damage. These strategies include: (1) controlling the synaptic or extra-synaptic release of glutamate, (2) selectively blocking the action of the glutamate receptor NMDAR subunit, (3) increasing glutamate metabolism, and reuptake in the brain and blood, and (4) regulating the glutamate system by GABA receptors and the microbiota–gut–brain axis. Based on these latest findings, it is expected to promote a substantial understanding of the complex glutamate signal transduction mechanism, thereby providing excellent neuroprotection research direction for human ischemic stroke (IS).

A Review on Preclinical Models of Ischemic Stroke: Insights Into the Pathomechanisms and New Treatment Strategies

BACKGROUND

Stroke is a serious neurovascular problem and the leading cause of disability and death worldwide. The disrupted demand to supply ratio of blood and glucose during cerebral ischemia develops hypoxic shock, and subsequently necrotic neuronal death in the affected regions. Multiple causal factors like age, sex, race, genetics, diet, and lifestyle play an important role in the occurrence as well as progression of post-stroke deleterious events. These biological and environmental factors may be contributed to vasculature variable architecture and abnormal neuronal activity. Since recombinant tissue plasminogen activator is the only clinically effective clot bursting drug, there is a huge unmet medical need for newer therapies for the treatment of stroke. Innumerous therapeutic interventions have shown promise in the experimental models of stroke but failed to translate it into clinical counterparts.

METHODS

Original publications regarding pathophysiology, preclinical experimental models, new targets and therapies targeting ischemic stroke have been reviewed since the 1970s.

RESULTS

We highlighted the critical underlying pathophysiological mechanisms of cerebral stroke and preclinical stroke models. We discuss the strengths and caveats of widely used ischemic stroke models, and commented on the potential translational problems. We also describe the new emerging treatment strategies, including stem cell therapy, neurotrophic factors and gut microbiome-based therapy for the management of post-stroke consequences.

CONCLUSION

There are still many inter-linked pathophysiological alterations with regards to stroke, animal models need not necessarily mimic the same conditions of stroke pathology and newer targets and therapies are the need of the hour in stroke research.

Circular noncoding RNA circ_0007865, serves as a competing endogenous RNA, targeting the miR-214-3p/FKBP5 axis to regulate oxygen-glucose deprivation-induced injury in brain microvascular endothelial cells

BACKGROUND

Ischemic stroke (IS) is a major cause of permanent morbidity and lifelong disability worldwide. Circular RNA (circRNA) circ_0007865 has been reported to be upregulated in acute ischemic stroke (AIS) patients. Also, AIS patients exhibited increased death of human brain microvascular endothelial cells (HBMECs). This study is designed to explore the role and mechanism of circ_0007865 in the oxygen-glucose deprivation (OGD)-induced cell damage in AIS.

METHODS

Circ_0007865, microRNA-214-3p (miR-214-3p), and FK506-binding protein 5 (FKBP5) levels were detected by real-time quantitative PCR. Cell proliferative angiogenesis, migration, and apoptosis were assessed by Cell Counting Kit-8, 5-ethynyl-2'-deoxyuridine, colony formation, tube formation, wound healing, transwell, and flow cytometry assays. B-cell lymphoma-2 (Bcl-2), Bcl-2-related X protein (Bax), cleaved caspase-3, and FKBP5 protein levels were determined by western blot assay. The binding relationship between miR-214-3p and circ_0007865 or FKBP5 was predicted by StarBase, and verified by a dual-luciferase reporter, RNA pull-down assay.

RESULTS

Circ_0007865 and FKBP5 were increased, and miR-214-3p was decreased in OGD-treated HBMECs. Furthermore, the silencing of circ_0007865 could promote cell proliferative angiogenesis, migration, and inhibit apoptosis in OGD-triggered HBMECs in vitro. Mechanically, circ_0007865 acted as a sponge of miR-214-3p to regulate FKBP5.

CONCLUSION

According to these results, circ_0007865 deficiency could attenuate OGD-induced HBMEC damage by modulating the miR-214-3p/FKBP5 axis, hinting at a promising therapeutic target for future acute IS therapy.

Ceruletide and Alpha-1 Antitrypsin as a Novel Combination Therapy for Ischemic Stroke

Ischemic stroke is a primary cause of morbidity and mortality worldwide. Beyond the approved thrombolytic therapies, there is no effective treatment to mitigate its progression. Drug repositioning combinational therapies are becoming promising approaches to identify new uses of existing drugs to synergically target multiple disease-response mechanisms underlying complex pathologies. Here, we used a systems biology-based approach based on artificial intelligence and pattern recognition tools to generate in silico mathematical models mimicking the ischemic stroke pathology. Combinational treatments were acquired by screening these models with more than 5 million two-by-two combinations of drugs. A drug combination (CA) formed by ceruletide and alpha-1 antitrypsin showing a predicted value of neuroprotection of 92% was evaluated for their synergic neuroprotective effects in a mouse pre-clinical stroke model. The administration of both drugs in combination was safe and effective in reducing by 39.42% the infarct volume 24 h after cerebral ischemia. This neuroprotection was not observed when drugs were given individually. Importantly, potential incompatibilities of the drug combination with tPA thrombolysis were discarded in vitro and in vivo by using a mouse thromboembolic stroke model with t-PA-induced reperfusion, revealing an improvement in the forepaw strength 72 h after stroke in CA-treated mice. Finally, we identified the predicted mechanisms of action of ceruletide and alpha-1 antitrypsin and we demonstrated that CA modulates EGFR and ANGPT-1 levels in circulation within the acute phase after stroke. In conclusion, we have identified a promising combinational treatment with neuroprotective effects for the treatment of ischemic stroke.

Drug Synergism as the Basis of Rational Neuroprotection

Optimization of the choice of neuroprotective therapy regimens in patients with cerebrovascular diseases (CVD), taking into account the synergism of drug interactions, is a basic approach in clinical practice. Unfortunately, modern pharmacology has no unified way of establishing synergistic spectra of drug actions, which would allow systematic investigation of the effects of combinations of drugs. An approach based on studying detailed mechanisms of action suggested combinations of drugs with the greatest possible synergism (by summation and potentiation of effects) for various directions in the treatment of neurological diseases. Examples of rational neuroprotection are considered, using Cortexin, citicoline, and antioxidants.

Neuroprotective Effects of Guanosine in Ischemic Stroke-Small Steps towards Effective Therapy

Guanosine (Guo) is a nucleotide metabolite that acts as a potent neuromodulator with neurotrophic and regenerative properties in neurological disorders. Under brain ischemia or trauma, Guo is released to the extracellular milieu and its concentration substantially raises. In vitro studies on brain tissue slices or cell lines subjected to ischemic conditions demonstrated that Guo counteracts destructive events that occur during ischemic conditions, e.g., glutaminergic excitotoxicity, reactive oxygen and nitrogen species production. Moreover, Guo mitigates neuroinflammation and regulates post-translational processing. Guo asserts its neuroprotective effects via interplay with adenosine receptors, potassium channels, and excitatory amino acid transporters. Subsequently, guanosine activates several prosurvival molecular pathways including PI3K/Akt (PI3K) and MEK/ERK. Due to systemic degradation, the half-life of exogenous Guo is relatively low, thus creating difficulty regarding adequate exogenous Guo distribution. Nevertheless, in vivo studies performed on ischemic stroke rodent models provide promising results presenting a sustained decrease in infarct volume, improved neurological outcome, decrease in proinflammatory events, and stimulation of neuroregeneration through the release of neurotrophic factors. In this comprehensive review, we discuss molecular signaling related to Guo protection against brain ischemia. We present recent advances, limitations, and prospects in exogenous guanosine therapy in the context of ischemic stroke.

Whether short peptides are good candidates for future neuroprotective therapeutics?

Neurodegenerative diseases are a broad group of largely debilitating, and ultimately terminal conditions resulting in progressive degeneration of different brain regions. The observed damages are associated with cell death, structural and functional deficits of neurons, or demyelination. The concept of neuroprotection concerns the administration of the agent, which should reverse some of the damage or prevent further adverse changes. A growing body of evidence suggested that among many classes of compounds considered as neuroprotective agents, peptides derived from natural materials or their synthetic analogs are good candidates. They presented a broad spectrum of activities and abilities to act through diverse mechanisms of action. Biologically active peptides have many properties, including antioxidant, antimicrobial, antiinflammatory, and immunomodulatory effects. Peptides with pro-survival and neuroprotective activities, associated with inhibition of oxidative stress, apoptosis, inflammation and are able to improve cell viability or mitochondrial functions, are also promising molecules of particular interest to the pharmaceutical industries. Peptide multiple activities open the way for broad application potential as therapeutic agents or ingredients of health-promoting functional foods. Significantly, synthetic peptides can be remodeled in numerous ways to have desired features, such as increased solubility or biological stability, as well as selectivity towards a specific receptor, and finally better membrane penetration. This review summarized the most common features of major neurodegenerative disorders, their causes, consequences, and reported new neuroprotective drug development approaches. The author focused on the unique perspectives in neuroprotection and provided a concise survey of short peptides proposed as novel therapeutic agents against various neurodegenerative diseases.

[The criteria for effectiveness of reperfusion therapy and neuroprotective therapy in ischemic stroke]

The narrative review discusses the data on efficacy and safety of reperfusion therapy (RT) and neuroprotective therapy in ischemic stroke. The influence of therapy on mortality, residual neurologic deficit and disability is analyzed. It was shown that RT (thrombolysis or mechanical thromboextraction) leads to significant decrease of residual neurologic deficit or disability. The influence of RT on mortality is controversial. There is some evidence that RT can increase early mortality due to hemorrhagic complications. Neuroprotective therapy is much less studied in stroke but is recognized as safe. Neuroprotective therapy (i.e. cerebrolysin) can diminish residual neurologic deficit and disability, while it has no influence on mortality.

Blood-Brain Barrier Damage in Ischemic Stroke and Its Regulation by Endothelial Mechanotransduction

Ischemic stroke, a major cause of mortality in the United States, often contributes to disruption of the blood-brain barrier (BBB). The BBB along with its supportive cells, collectively referred to as the “neurovascular unit,” is the brain’s multicellular microvasculature that bi-directionally regulates the transport of blood, ions, oxygen, and cells from the circulation into the brain. It is thus vital for the maintenance of central nervous system homeostasis. BBB disruption, which is associated with the altered expression of tight junction proteins and BBB transporters, is believed to exacerbate brain injury caused by ischemic stroke and limits the therapeutic potential of current clinical therapies, such as recombinant tissue plasminogen activator. Accumulating evidence suggests that endothelial mechanobiology, the conversion of mechanical forces into biochemical signals, helps regulate function of the peripheral vasculature and may similarly maintain BBB integrity. For example, the endothelial glycocalyx (GCX), a glycoprotein-proteoglycan layer extending into the lumen of bloods vessel, is abundantly expressed on endothelial cells of the BBB and has been shown to regulate BBB permeability. In this review, we will focus on our understanding of the mechanisms underlying BBB damage after ischemic stroke, highlighting current and potential future novel pharmacological strategies for BBB protection and recovery. Finally, we will address the current knowledge of endothelial mechanotransduction in BBB maintenance, specifically focusing on a potential role of the endothelial GCX.

Cerebrolysin for acute ischaemic stroke

BACKGROUND

Cerebrolysin is a mixture of low-molecular-weight peptides and amino acids derived from porcine brain that has potential neuroprotective properties. It is widely used in the treatment of acute ischaemic stroke in Russia, Eastern Europe, China, and other Asian and post-Soviet countries. This is an update of a review first published in 2010 and last updated in 2017.

OBJECTIVES

To assess the benefits and harms of Cerebrolysin for treating acute ischaemic stroke.

SEARCH METHODS

We searched the Cochrane Stroke Group Trials Register, CENTRAL, MEDLINE, Embase, Web of Science Core Collection, with Science Citation Index, LILACS, OpenGrey, and a number of Russian databases in October 2019. We also searched reference lists, ongoing trials registers, and conference proceedings.

SELECTION CRITERIA

Randomised controlled trials (RCTs) comparing Cerebrolysin, started within 48 hours of stroke onset and continued for any length of time, with placebo or no treatment in people with acute ischaemic stroke.

DATA COLLECTION AND ANALYSIS

Two review authors independently applied the inclusion criteria, assessed trial quality and risk of bias, extracted data, and applied GRADE criteria to the evidence.

MAIN RESULTS

Seven RCTs (1601 participants) met the inclusion criteria of the review. In this update we re-evaluated risk of bias through identification, examination, and evaluation of study protocols and judged it to be low, unclear, or high across studies: unclear for all domains in one study, and unclear for selective outcome reporting across all studies; low for blinding of participants and personnel in four studies and unclear in the remaining three; low for blinding of outcome assessors in three studies and unclear in four studies. We judged risk of bias to be low in two studies and unclear in the remaining five studies for generation of allocation sequence; low in one study and unclear in six studies for allocation concealment; and low in one study, unclear in one study, and high in the remaining five studies for incomplete outcome data. The manufacturer of Cerebrolysin supported four multicentre studies, either totally, or by providing Cerebrolysin and placebo, randomisation codes, research grants, or statisticians. We judged three studies to be at high risk of other bias and the remaining four studies to be at unclear risk of other bias. All-cause death: we extracted data from six trials (1517 participants). Cerebrolysin probably results in little to no difference in all-cause death: risk ratio (RR) 0.90, 95% confidence interval (CI) 0.61 to 1.32 (6 trials, 1517 participants, moderate-quality evidence). None of the included trials reported on poor functional outcome defined as death or dependence at the end of the follow-up period or early death (within two weeks of stroke onset), or time to restoration of capacity for work and quality of life. Only one trial clearly reported on the cause of death: cerebral infarct (four in the Cerebrolysin and two in the placebo group), heart failure (two in the Cerebrolysin and one in the placebo group), pulmonary embolism (two in the placebo group), and pneumonia (one in the placebo group). Serious adverse events (SAEs): Cerebrolysin probably results in little to no difference in the total number of people with SAEs (RR 1.15, 95% CI 0.81 to 1.65, 4 RCTs, 1435 participants, moderate-quality evidence). This comprised fatal SAEs (RR 0.90, 95% CI 0.59 to 1.38) and an increase in the total number of people with non-fatal SAEs (RR 2.15, 95% CI 1.01 to 4.55, P = 0.047, 4 trials, 1435 participants, moderate-quality evidence). In the subgroup of dosing schedule 30 mL for 10 days (cumulative dose 300 mL), the increase was more prominent: RR 2.86, 95% CI 1.23 to 6.66, P = 0.01 (2 trials, 1189 participants). Total number of people with adverse events: four trials reported on this outcome. Cerebrolysin may result in little to no difference in the total number of people with adverse events: RR 0.97, 95% CI 0.85 to 1.10, P = 0.90, 4 trials, 1435 participants, low-quality evidence. Non-death attrition: evidence from six trials involving 1517 participants suggests that Cerebrolysin results in little to no difference in non-death attrition, with 96 out of 764 Cerebrolysin-treated participants and 117 out of 753 placebo-treated participants being lost to follow-up for reasons other than death (very low-quality evidence).

AUTHORS' CONCLUSIONS

Moderate-quality evidence indicates that Cerebrolysin probably has little or no beneficial effect on preventing all-cause death in acute ischaemic stroke, or on the total number of people with serious adverse events. Moderate-quality evidence also indicates a potential increase in non-fatal serious adverse events with Cerebrolysin use.

A novel free radical scavenger, NSP-116, ameliorated the brain injury in both ischemic and hemorrhagic stroke models

Reperfusion injury is a serious problem in ischemic stroke therapy, which leads to neuronal damage and intracranial hemorrhage (ICH). A novel free radical scavenger, NSP-116, has anti-oxidative effect and may ameliorate reperfusion injury. The purpose of this study was to investigate the effects of NSP-116 on both ischemic and hemorrhagic stroke models. First, we assessed whether NSP-116 has protective effects in vitro. Pre-treatment of NSP-116 decreased neuronal cell damage induced by H₂O₂ or LPS. Moreover, NSP-116 also suppressed mitochondria damage and apoptosis in H₂O₂-induced neuronal injury model. Based on these results, we used a middle cerebral artery occlusion (MCAO)-induced ischemic stroke model or a collagenase-induced ICH model. Using the MCAO model, we evaluated the cerebral blood flow (CBF), neurological deficit, and infarct volume. Hematoma volume was assessed at 3 days after ICH. In the MCAO model, oral administration of NSP-116 at 30 mg/kg attenuated the reduction of CBF, neurological deficits, and infarct formation. Interestingly, NSP-116 also ameliorated hematoma expansion and neurological deficits in the ICH model. Additionally, pre-treatment of NSP-116 suppressed the brain microvascular endothelial cell death induced by collagenase treatment. Collectively, our findings indicated that oral administration of NSP-116 attenuates both ischemic and hemorrhagic brain injuries after stroke.