Translational Stroke Research

In the present study, we used a comprehensive cellular toxicity (CeeTox) analysis panel to determine the toxicity profile for CNB-001 [4-((1E)-2-(5-(4-hydroxy-3-methoxystyryl-)-1-phenyl-1H-pyrazoyl-3-yl)vinyl)-2-methoxy-phenol)], which is a hybrid molecule created by combining cyclohexyl bisphenol A, a molecule with neurotrophic activity and curcumin, a spice with neuroprotective activity. CNB-001 is a lead development compound since we have recently shown that CNB-001 has significant preclinical efficacy both in vitro and in vivo. In this study, we compared the CeeTox profile of CNB-001 with two neuroprotective molecules that have been clinically tested for efficacy: the hydrophilic free radical spin trap agent NXY-059 and the hydrophobic free radical scavenger edaravone (Radicut). CeeTox analyses using a rat hepatoma cell line (H4IIE) resulted in estimated C Tox value (i.e., sustained concentration expected to produce toxicity in a rat 14-day repeat dose study) of 42 μM for CNB-001 compared with >300 μM for both NXY-059 and Radicut. The CeeTox panel suggests that CNB-001 produces some adverse effects on cellular adenosine triphosphate content, membrane toxicity, glutathione content, and cell mass (or number), but only with high concentrations of the drug. After a 24-h exposure, the drug concentration that produced a half-maximal response (TC50) on the measures noted above ranges from 55 to 193 μM. Moreover, all CNB-001-induced changes in the markers were coincident with loss of cell number, prior to acute cell death as measured by membrane integrity, suggesting a cytostatic effect of CNB-001. NXY-059 and Radicut did not have acute toxic effects on H4IIE cells. We also found that CNB-001 resulted in an inhibition of ethoxyresorufin-o-deethylase activity, indicating that the drug may affect cytochrome P4501A activity and that CNB-001 was metabolically unstable using a rat microsome assay system. For CNB-001, an estimated in vitro efficacy/toxicity ratio is 183–643-fold, suggesting that there is a significant therapeutic safety window for CNB-001 and that it should be further developed as a novel neuroprotective agent to treat stroke.

Female sex steroids, particularly estrogens, contribute to the sexually dimorphic response observed in cerebral ischemic outcome, with females being relatively protected compared to males. Using a mouse model of cardiac arrest and cardiopulmonary resuscitation, we previously demonstrated that estrogen neuroprotection is mediated in part by the estrogen receptor β, with no involvement of estrogen receptor α. In this study, we examined the neuroprotective effect of the novel estrogen receptor, G protein-coupled estrogen receptor 1 (GPER1/GPR30). Male mice administered with the GPR30 agonist G1 exhibited significantly reduced neuronal injury in the hippocampal CA1 region and striatum. The magnitude of neuroprotection observed in G1-treated mice was indistinguishable from estrogen-treated mice, implicating GPR30 in estrogen neuroprotection. Real-time quantitative RT-PCR indicates that G1 treatment increases expression of the neuroprotective ion channel, small-conductance calcium-activated potassium channel 2. We conclude that GPR30 agonists show promise in reducing brain injury following global cerebral ischemia.

Clinical studies have investigated the effects of using sodium-glucose co-transporter-2 (SGLT2) inhibitors on the development of new-onset stroke (NOS) in patients with type 2 diabetes (T2D) and chronic kidney disease (CKD), but the findings are inconsistent. This study aimed to examine the association between the use of SGLT2 inhibitors and NOS risk in patients with T2D and CKD. We conducted a nationwide retrospective cohort study using data from the Taiwan Health Insurance Review and Assessment Service database for the years 2004 to 2019. The primary outcome was the risk of incident stroke, which was estimated using hazard ratios (HRs) and 95% confidence intervals (CIs). We used multiple Cox regression modeling to analyze the association between SGLT2 inhibitor use and the risk of stroke in patients with T2D and CKD. In a cohort of 113,710 patients with T2D and CKD who were using SGLT2 inhibitors and 227,420 patients with T2D and CKD who were not using SGLT2 inhibitors, after applying a 1:2 sex- and age-matching strategy, 2,842 and 7,169 NOS events were recorded, respectively. The event rate per 10,000 person-months was 10.60 (95% CI 10.21 to 11.03) for SGLT2 inhibitor users and 13.71 (13.39–14.03) for non-SGLT2 inhibitor users. After adjusting for the index year, sex, age, comorbidities, and concurrent medication, there was a decreased risk of NOS for SGLT2 inhibitor users (adjusted HR 0.80; 95% CI 0.77–0.84) compared with non-SGLT2 inhibitor users. The sensitivity test for the propensity score 1:1-matched analyses showed similar results (adjusted HR 0.80; 95% CI 0.76–0.84). The type of SGLT2 inhibitor subgroup analysis for incident stroke showed consistent results. We concluded that the use of SGLT2 inhibitors in patients with T2D and CKD was associated with significantly low rates of NOS. The significantly low rates of NOS in patients with T2D and CKD were greater among females and less than 50 years patients.

Erythrolysis occurs in the clot after intracerebral hemorrhage (ICH), and the release of hemoglobin causes brain injury, but it is unclear when such lysis occurs. The present study examined early erythrolysis in rats. ICH rats had an intracaudate injection of 100 μl autologous blood, and sham rats had a needle insertion. All rats had T2 and T2* magnetic response imaging (MRI) scanning, and brains were used for histology and CD163 (a hemoglobin scavenger receptor) and DARPP-32 (a neuronal marker) immunohistochemistry. There was marked heterogeneity within the hematoma on T2* MRI, with a hyperintense or isointense core and a hypointense periphery. Hematoxylin and eosin staining in the same animals showed significant erythrolysis in the core with the formation of erythrocyte ghosts. The degree of erythrolysis correlated with the severity of perihematomal neuronal loss. Perihematomal CD163 was increased by day 1 after ICH and may be involved in clearing hemoglobin caused by early hemolysis. Furthermore, ICH resulted in more severe erythrolysis, neuronal loss, and perihematomal CD163 upregulation in spontaneously hypertensive rats compared to Wistar-Kyoto rats. In conclusion, T2*MRI-detectable early erythrolysis occurred in the clot after ICH and activated CD163. Hypertension is associated with enhanced erythrolysis in the hematoma.

Stem cells such as mesenchymal stem cells (MSCs) enhance neurological recovery in preclinical stroke models by secreting extracellular vesicles (EVs). Since previous reports have focused on the application of MSC-EVs only, the role of the most suitable host cell for EV enrichment and preclinical stroke treatment remains elusive. The present study aimed to evaluate the therapeutic potential of EVs derived from neural progenitor cells (NPCs) following experimental stroke. Using the PEG technique, EVs were enriched and characterized by electron microscopy, proteomics, rt-PCR, nanosight tracking analysis, and Western blotting. Different dosages of NPC-EVs displaying a characteristic profile in size, shape, cargo protein, and non-coding RNA contents were incubated in the presence of cerebral organoids exposed to oxygen-glucose deprivation (OGD), significantly reducing cell injury when compared with control organoids. Systemic administration of NPC-EVs in male C57BL6 mice following experimental ischemia enhanced neurological recovery and neuroregeneration for as long as 3 months. Interestingly, the therapeutic impact of such NPC-EVs was found to be not inferior to MSC-EVs. Flow cytometric analyses of blood and brain samples 7 days post-stroke demonstrated increased blood concentrations of B and T lymphocytes after NPC-EV delivery, without affecting cerebral cell counts. Likewise, a biodistribution analysis after systemic delivery of NPC-EVs revealed the majority of NPC-EVs to be found in extracranial organs such as the liver and the lung. This proof-of-concept study supports the idea of EVs being a general concept of stem cell–induced neuroprotection under stroke conditions, where EVs contribute to reverting the peripheral post-stroke immunosuppression.

About half of acute stroke patients treated with mechanical thrombectomy (MT) do not show clinical improvement despite successful recanalization. Early arterial reocclusion (EAR) may be one of the causes that explain this phenomenon. We aimed to analyze the incidence and clinico-radiological correlations of EAR after successful MT. A consecutive series of patients treated with MT between 2010 and 2018 at a single-center included in a prospective registry was retrospectively reviewed. Specific inclusion criteria for the analysis were (1) successful recanalization after MT and (2) availability of pretreatment CT perfusion and follow-up MRI. EAR was evaluated in the follow-up MR angiography. Adjusted regression models were used to analyze the association of EAR with pretreatment variables, infarct growth, final infarct volume, and clinical outcome at 90 days (ordinal distribution of the modified Rankin Scale scores). Out of 831 MT performed, 218 (26%) patients fulfilled inclusion criteria, from whom 13 (6%) suffered EAR. In multivariate analysis controlled by confounders, EAR was independently associated with poor clinical outcome (aOR = 3.2, 95%CI = 1.16–9.72, p = 0.039), greater final infarct volume (aOR = 3.8, 95%CI = 1.93–7.49, p < 0.001), and increased infarct growth (aOR = 8.5, CI95% = 2.04–34.70, p = 0.003). According to mediation analyses, the association between EAR and poor clinical outcome was mainly explained through its effects on final infarct volume and infarct growth. Additionally, EAR was associated with non-cardioembolic etiology (adjusted Odds Ratio (aOR) = 10.1, 95%CI = 1.25–81.35, p = 0.030) and longer procedural time (aOR = 2.6, 95%CI = 1.31–5.40, p = 0.007). Although uncommon, EAR hampers the benefits of successful recanalization after MT resulting in increased infarct growth and larger final lesions.

Tissue plasminogen activator (tPA) is a multifunctional protease. In blood tPA is best understood for its role in fibrinolysis, whereas in the brain tPA is reported to regulate blood–brain barrier (BBB) function and to promote neurodegeneration. Thrombolytic tPA is used for the treatment of ischemic stroke. However, its use is associated with an increased risk of hemorrhagic transformation. In blood the primary regulator of tPA activity is plasminogen activator inhibitor 1 (PAI-1), whereas in the brain, its primary inhibitor is thought to be neuroserpin (Nsp). In this study, we compare the effects of PAI-1 and Nsp deficiency in a mouse model of ischemic stroke and show that tPA has both beneficial and harmful effects that are differentially regulated by PAI-1 and Nsp. Following ischemic stroke Nsp deficiency in mice leads to larger strokes, increased BBB permeability, and increased spontaneous intracerebral hemorrhage. In contrast, PAI-1 deficiency results in smaller infarcts and increased cerebral blood flow recovery. Mechanistically, our data suggests that these differences are largely due to the compartmentalized action of PAI-1 and Nsp, with Nsp deficiency enhancing tPA activity in the CNS which increases BBB permeability and worsens stroke outcomes, while PAI-1 deficiency enhances fibrinolysis and improves recovery. Finally, we show that treatment with a combination therapy that enhances endogenous fibrinolysis by inhibiting PAI-1 with MDI-2268 and reduces BBB permeability by inhibiting tPA-mediated PDGFRα signaling with imatinib significantly reduces infarct size compared to vehicle-treated mice and to mice with either treatment alone.

The objective of this study was to elucidate the role of magnesium sulfate in patients with subarachnoid hemorrhagic (SAH) brain injury. Studies for the meta-analysis were identified from PubMed (1966–2009), Embase (1980–2009), and two Chinese journals (1989–2009). Paper selection was based on randomized controlled trials comparing magnesium sulfate to placebo treatment in patients with SAH. Two independent review authors extracted the data and assessed trial quality. Meta-analysis was performed using the Cochrane Review Manager software. Five trials involving 482 patients were included in the review. Magnesium sulfate reduced the risk of poor outcome and reduced the occurrence of delayed cerebral ischemia. In the treatment groups, relative risk for poor outcome was 0.73 (CI 0.57–0.93) and 0.66 (CI 0.47–0.92) for delayed cerebral ischemia. Case fatality assessment at 3 to 6 months did not show statistically significant data (relative risk 0.88, CI 0.61–1.29). Magnesium sulfate appears to be an effective treatment option in the management of SAH. Further clinical trials are needed before magnesium sulfate can become a routine treatment for SAH.