Novel Situations of Endothelial Injury in Stroke — Mechanisms of Stroke and Strategy of Drug Development: Novel Mechanism of the Expression and Amplification of Cell Surface–Associated Fibrinolytic Activity Demonstrated by Real-Time Imaging Analysis

Hydrogen Inhalation Attenuates Oxidative Stress Related Endothelial Cells Injury After Subarachnoid Hemorrhage in Rats

Background: Subarachnoid hemorrhage (SAH) is a devastating cerebrovascular disease with poor clinical outcome. Nucleotide binding and oligomerization domain-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome serves a key role in inflammatory response, which may lead to endothelial cell injury and blood-brain barrier (BBB) disruption. Hydrogen (H₂) is considered a neuroprotective antioxidant. This study was set out to explore whether hydrogen inhalation protects against SAH induced endothelial cell injury, BBB disruption, microthrombosis and vasospasm in rats.

Methods: One hundred eighty-two male SD rats were used for the study. SAH was induced by endovascular perforation. H2 at a concentration of 3.3% was inhaled beginning at 0.5 h after SAH for duration of 30, 60 or 120 min, followed by single administration or once daily administration for 3 days. The temporal expression of NLRP3 and ASC in the brain was determined, with the effect of hydrogen inhalation evaluated. In addition, brain water content, oxidative stress markers, inflammasome, apoptotic markers, microthrombosis, and vasospasm were evaluated at 24 or 72 h after SAH.

Results: The expression of NLRP3 and ASC were upregulated after SAH associated with elevated expression of MDA, 8-OHdG, 4-HNE, HO-1, TLR4/NF-κB, inflammatory and apoptotic makers. Hydrogen inhalation reduced the expression of these inflammatory and apoptotic makers in the vessels, brain edema, microthrombi formation, and vasospasm in rats with SAH relative to control. Hydrogen inhalation also improved short-term and long-term neurological recovery after SAH.

Conclusion: Hydrogen inhalation can ameliorate oxidative stress related endothelial cells injury in the brain and improve neurobehavioral outcomes in rats following SAH. Mechanistically, the above beneficial effects might be related to, at least in part, the inhibition of activation of ROS/NLRP3 axis.

Cornel iridoid glycoside reduces infarct size measured by magnetic resonance imaging and improves neurological function after focal cerebral ischemia in rats

OBJECTIVE

To investigate the effect of cornel iridoid glycoside (CIG), an ingredient extracted from traditional Chinese herb Cornus offificinalis, on neurological function and infarct size in rats as measured by magnetic resonance imaging (MRI) after ischemic stroke.

METHODS

Sprague-Dawley rats were divided into three group: control (n=11), model (n=20) and CIG (n=16) groups. Rats in the model and CIG groups underwent 90-min middle cerebral artery occlusion (MCAO) followed by reperfusion. Their neurological defect was measured by using a modified neurological severity score (mNSS). T2-weighted MRI (T2-MRI) of the brain was performed in vivo from 2 to 28 days after MCAO. The infarct volume in the brain was also measured using 2,3,5-triphenyltetrazolium chloride (TTC) staining 28 days after stroke.

RESULTS

CIG, 60 mg/(kg day), administered by oral gavage starting from 6 h after the onset of MCAO improved neurological function at 7, 14, 21, and 28 days post occlusion (P<0.05 orP<0.01) and decreased mortality. The infarct volumes computed from the T2-MR images were reduced in the CIG-treated group compared with the model group at 7, 14 and 28 days after MCAO (P<0.05); and the rate at which the infarct volume decreased from 2 to 28 days was higher in the CIG-treated group than that in the model group (P<0.05). The infarct volumes measured by TTC staining were also decreased 28 days after stroke (P<0.05).

CONCLUSION

CIG treatment, starting from 6 h after MCAO, reduced infarct size in the brain as measured by MRI and improved neurological function 2-28 days after focal cerebral ischemia in rats, suggesting that CIG could be a clinical application in improving stroke treatment.

Functional characterization of fibrinolytic metalloproteinases (colombienases) isolated from Bothrops colombiensis venom

Researchers trying to improve the safety and efficacy of fibrinolytic therapy have been isolating fibrinolytic enzymes from snake venoms. Two fibrinolytic enzymes, colombienases 1 and 2, with significant activity have been isolated from the venom of Bothrops colombiensis.

METHODS

The colombienases were characterized for various biological activities which include hemorrhagic, fibrinogenolytic, proteolytic, hemolytic, edematogenic and cytotoxic.

RESULTS

Colombienases directly acted on fibrin by degrading fibrinogen Aα and Bβ chains without activating the fibrinolytic system (plasminogen/plasmin), additionally colombienase-2 degraded fibrinogen γ chains as well as the fibronectin molecule. Laminin and type IV collagen were colombienases resistant. Gelatin-zymogram activity was present in B. colombiensis venom (BcV) bands between 64 and 148 kDa. All activities were abolished by metalloproteinases inhibitors. Both enzymes lacked hemorrhagic, hemolytic, cytotoxic, plasminogen activator and coagulant activities.

CONCLUSIONS

Both colombienases had direct fibrino(geno)lytic activity without other toxic side effects including in vivo hemorrhaging, which could be promising in terms of therapeutic potential as thrombolytic agents.

Cocktail blood biomarkers: prediction of clinical outcomes in patients with acute ischemic stroke

BACKGROUND

Timely prediction of stroke outcomes is important for proper personalized treatment. In the present study, we aimed to develop cocktail blood biomarkers to increase prediction efficiency using a combination of hemostasis, inflammatory and repair-related biomarkers.

METHODS

105 patients suffering from acute ischemic stroke were divided into good outcome group and poor outcome group by modified Rankin Scale (mRS). Cytokines including CD40L, IFN-γ, IL-1α, IL-1β, IL-6, IL-8, IL-17 and TNF-α, as well as hemostasis markers fibrinogen, fibrin degradation products (FDP), D-dimer, tissue plasminogen activator, and plasminogen activation inhibitor-1 in plasma were examined by ELISA. Repair-related biomarker microRNA-210 (miR-210) was measured by real-time PCR. The prediction efficiency was explored by receiver operator characteristic analysis.

RESULTS

We demonstrated that FDP, IL-6 and miR-210 levels were closely associated with mRS in stroke patients. The prediction sensitivity of FDP, IL-6 and miR-210 for stroke outcome was 72.0, 86.7 and 82.5%, respectively. Using a combination of biomarkers including FDP, IL-6 and miR-210, the prognostic sensitivity of ischemic stroke increased to 95.2%.

CONCLUSION

The combination of FDP, IL-6 and miR-210 has a high sensitivity for predicting stroke recovery, it serves as a potential cocktail blood biomarker. It provides a novel approach for stroke prognosis.