Zhaohui He

CHOP Silencing Reduces Acute Brain Injury in the Rat Model of Subarachnoid Hemorrhage

Background and Purpose— Endoplasmic reticulum stress triggers apoptotic cascades in neurons of the central nervous system after subarachnoid hemorrhage. The aim of this work was to study the mechanism of neuroprotection conferred by targeting cyclophosphamide, doxorubicin, vincristine, and prednisone (CHOP) in the acute brain injury following subarachnoid hemorrhage. Methods— A total of 172 rats were used. Endovascular perforation induced subarachnoid hemorrhage. Two small interfering RNAs for CHOP were injected 24 hours before hemorrhage induction. At 24 or 72 hours, rats were neurologically evaluated and euthanized. The brains were recovered for molecular biology and histology studies. Results— Western blot analysis revealed effective silencing of CHOP associated with suppression of Bim-Caspase-3 apoptotic pathway. Moreover, the antiapoptotic Bcl2 was found upregulated with CHOP siRNA treatment. A reduced number of TUNEL-positive cells in the subcortex and in the hippocampus reflected histological protection. CHOP siRNA treatment ameliorated intracranial sequelae of and improved functional performance. Conclusions— We conclude that CHOP silencing alleviates early brain injury following subarachnoid hemorrhage via inhibiting apoptosis and that CHOP siRNA treatment has a clinical potential for patients with this type of hemorrhagic stroke.

Isoflurane Enhanced Hemorrhagic Transformation by Impairing Antioxidant Enzymes in Hyperglycemic Rats With Middle Cerebral Artery Occlusion

Background and Purpose— Because the potential neuroprotective effect of isoflurane is controversial, we attempted to study whether isoflurane after treatment provides neuroprotection in a rat model of hyperglycemia-induced ischemic hemorrhagic transformation. Methods— Rats received an injection of 50% dextrose (6 mL/kg intraperitoneally) and had a middle cerebral artery occlusion 30 minutes later. Four groups were included: sham-operated, ischemia/reperfusion, isoflurane treatment, and vehicle groups. In the treatment group, after 2 hours of ischemia, 2% isoflurane was administered at the onset of reperfusion. We measured the level of blood glucose at 0, 2.5, 4.5, and 6.5 hours after dextrose injection. Infarct and hemorrhagic volumes, neurological scores, oxidative stress (malondialdehyde, 4-hydroxy-2-nonenal, and nitrotyrosine) and the activities of superoxide dismutase and catalase were measured at 24 hours after ischemia. Results— Isoflurane had no effects on blood glucose, it failed to reduce infarct, hemorrhage volume, and brain edema, and it enhanced neurobehavioral deficits when compared with the ischemia/reperfusion group at 24 hours after middle cerebral artery occlusion. On the contrary, isoflurane exacerbated these parameters compared with the vehicle group. In addition, it increased the expressions of malondialdehyde, 4-hydroxy-2-nonenal, and nitrotyrosine, and it decreased the activities of superoxide dismutase and catalase compared to the vehicle group. Conclusions— Isoflurane after treatment worsened physiological and neurological outcomes in this ischemia hyperglycemia-induced hemorrhagic transformation possibly by impairing the antioxidant defense system.

Matrix metalloproteinase-9 potentiates early brain injury after subarachnoid hemorrhage

Abstract Objective: This study investigated the role of matrix metalloproteinase-9 (MMP-9) in early brain injury after subarachnoid hemorrhage (SAH). Method: Sprague–Dawley male rats (n=36) weighing between 250 and 300 g were used. SAH was produced by injecting autologous arterial blood into the pre-chiasmatic cistern. MMP-9 protein expression and activity were measured by Western blot and zymogram; laminin expression and neuronal cell in hippocampus were studied by immunohistochemistry and TUNEL staining at 24 hours after SAH in the presence or absence of a selective MMP-9 inhibitor SB-3CT. Result: MMP-9 was activated by SAH and inhibited by SB-3CT at 24 hours after SAH (p<0.01). Laminin, the substrate of MMP-9, was decreased at 24 hours after SAH, and SB-3CT prevented laminin degradation. The number of TUNEL-positive neurons in hippocampus was increased after SAH and decreased by SB-3CT (p<0.01). In addition, brain water content and neurological functional abnormalities were attenuated by SB-3CT. Conclusion: MMP-9 may be involved in early brain injury through degradation of laminin and neuronal death, and inhibition of MMP-9 may be a potential direction for brain protection after SAH.

Targeting C/EBP homologous protein with siRNA attenuates cerebral vasospasm after experimental subarachnoid hemorrhage.

Endothelial apoptosis plays a major role in the development of cerebral vascular spasm after subarachnoid hemorrhage (SAH). C/EBP homologous protein (CHOP) orchestrates apoptosis in a variety of cell types in response to endoplasmic reticulum (ER) stress, implicated in the brain injury after SAH. However, the role of CHOP in the mechanism of cerebral vasospasm (CVS) after SAH remains unexplored. The aim of this study was to evaluate the effect of CHOP silencing on endothelial apoptosis and CVS following subarachnoid hemorrhage in the rat. The study was conducted on 65 rats and employed endovascular perforation model of SAH. CHOP siRNAs were injected 24 h prior to the hemorrhage. At 72 h after SAH brains with basilar arteries (BA) were collected from euthanized rats for laboratory investigations. Triple fluorescence stain revealed expression of CHOP in cerebral vascular endothelia after SAH. Marked reduction of CHOP protein and the reduction of its downstream signaling effectors, bim and caspase-3, were found in BA with Western blot analysis. CHOP silencing reduced number of apoptotic endothelial cells in BA, and increased BA diameter after SAH. The amelioration of CVS was associated with reduced neuronal injury in cerebral tissues. In conclusion, CHOP siRNA treatment can effectively combat apoptotic mechanisms of cerebral vasospasm set in motion by subarachnoid bleeding.

Delayed Intracranial Hemorrhage Associated with Antiplatelet Therapy in Stent-Assisted Coil Embolized Cerebral Aneurysms

Administration of oral clopidogrel plus aspirin is the most important regimen to reduce thromboembolic complications in stent-assisted coil embolization of cerebral aneurysm. However, such therapy may increase the risk of hemorrhage. The purpose of this study is to analyze the effect of two different antiplatelet regimens on hemorrhagic and thromboembolic complication rates around the stent-assisted coil embolization period. Records over a 2-year period were reviewed in a retrospective cohort study. For 49 consecutive stent-assisted coil embolization procedures over 41 patients, nine patients received routine antiplatelet drugs (300 mg aspirin and 75 mg clopidogrel) for 3 days before embolization, and 32 received a loading dose of antiplatelet drugs (300 mg aspirin and 300 mg clopidogrel) just before induction of anesthesia. Delayed intracerebral hemorrhage (DIH) was observed more often in the routine antiplatelet group (2/9 cases, 22.2%) in comparison with the loading group (0/32 cases, 0%; P = 0.044; Fisher exact test). The two hemorrhagic cases were both female, and occurred within 24 h of postembolization. The thromboembolic complication rates were not significantly different between the two groups. Oral administration of routine antiplatelet drugs for 3 days before stent-assisted coil embolization possibly increases the risk of delayed intracranial hemorrhage, compared to loading group. Symptomatic thromboembolic complications have no significant difference in the two different regimens.

Value of noninvasive imaging in follow-up of intracranial aneurysm.

Follow-up is necessary for treated and untreated aneurysms. The purpose of this study is to assess the results of treated aneurysms, the development of untreated aneurysms and the incidence of new aneurysms through short-term follow-up with noninvasive imaging, including CTA and MRA. More-than-once follow-up imaging with either CTA or MRA was performed in 73 patients, 65 of them suffering SAH. CTA was performed in 46 patients with clipped aneurysms, 9 patients with coiled aneurysms and 8 cases with untreated aneurysms. MRA was performed in ten patients with coiled aneurysms. CTA follow-up demonstrated that in 48 clipped aneurysms, 47 aneurysms completely disappeared; one aneurysm with neck remnant and one new aneurysm was found. No recurrence was found after microsurgical clipping. CTA follow-up provided limited information for ten coiled aneurysms because of poor quality images due to artifacts from coil. MRA follow-up of 12 coiled aneurysms showed there were no recanalization, recurrence or new aneurysm. In 20 untreated aneurysms, 19 stayed unchanged, and one aneurysm automatically disappeared. The newest generation of CTA and MRA can be used for following-up of intracranial aneurysms, and is more readily accepted by Chinese patients because of convenience, non-invasiveness and low price.

Expression and Role of COMT in a Rat Subarachnoid Hemorrhage Model

OBJECTIVE The present study aimed to investigate the expression of COMT mRNA and protein and detect the plasma content of catecholamine (CA), the diameter and thickness of the basilar artery in the early stage of subarachnoid hemorrhage (SAH) to explore the role of COMT in SAH. METHODS SAH was induced by injection of nonheparinized autologous arterial blood into the chiasmatic cistern. RT-PCR and Western blotting were used to detect the mRNA and protein levels of COMT in the rat striatum at different time points (6, 12, 24, 48, and 72 h after SAH). High performance liquid chromatography was performed to detect plasma CA. With HE staining, the basilar artery diameter and its thickness were measured. RESULTS Compared with the normal group and sham group, the increased expression of mRNA and protein of COMT began at 6 h after SAH (P<0.01), which peaked at 12 h (P<0.01); it began to drop 24 h after SAH (P<0.01). However, 48 h after SAH, the level of COMT (mRNA and protein) was still higher than that of the normal group (P<0.01). Three days after SAH, the expression of COMT nearly reached normal levels (P>0.05). For rats undergoing SAH, plasma CA began to increase 6h after injury, which reached a maximum at 24 h after SAH, and then started to drop. Three days later, it still remained elevated compared with that of the normal group and sham group (P<0.01). The most marked contraction and increased wall thickness of the basilar artery were found at 24 h after SAH (P<0.01), which at least lasted for 2 days (P<0.01), and 72 h after injury, the diameter and thickness of the basilar artery almost reached normal levels (P>0.05). CONCLUSION (1) SAH could induce the expression of COMT in the rat striatum in the early stage. (2) Plasma CA levels were significantly elevated in the early stage of SAH accompanied by cerebrovascular vasospasm (CVS). (3) In the early stage of SAH, increased plasma and CVS may be associated with the insufficient increase and persistence of COMT expression.

PPARβ/δ, a Novel Regulator for Vascular Smooth Muscle Cells Phenotypic Modulation and Vascular Remodeling after Subarachnoid Hemorrhage in Rats

Cerebral vascular smooth muscle cell (VSMC) phenotypic switch is involved in the pathophysiology of vascular injury after aneurysmal subarachnoid hemorrhage (aSAH), whereas the molecular mechanism underlying it remains largely speculative. Peroxisome proliferator-activated receptor β/δ (PPARβ/δ) has been implicated to modulate the vascular cells proliferation and vascular homeostasis. In the present study, we investigated the potential role of PPARβ/δ in VSMC phenotypic switch following SAH. Activation of PPARβ/δ by GW0742 and adenoviruses PPARβ/δ (Ad-PPARβ/δ) significantly inhibited hemoglobin-induced VSMC phenotypic switch. However, the effects of PPARβ/δ on VSMC phenotypic switch were partly obstacled in the presence of LY294002, a potent inhibitor of Phosphatidyl-Inositol-3 Kinase-AKT (PI3K/AKT). Furthermore, following study demonstrated that PPARβ/δ-induced PI3K/AKT activation can also contribute to Serum Response Factor (SRF) nucleus localization and Myocardin expression, which was highly associated with VSMC phenotypic switch. Finally, we found that Ad-PPARβ/δ positively modulated vascular remodeling in SAH rats, i.e. the diameter of basilar artery and the thickness of vessel wall. In addition, overexpression of PPARβ/δ by adenoviruses significantly improved neurological outcome. Taken together, this study identified PPARβ/δ as a useful regulator for VSMC phenotypic switch and vascular remodeling following SAH, providing novel insights into the therapeutic strategies of delayed cerebral ischemia.

Monitoring of the Effect of Cerebral Autoregulation on Delayed Cerebral Ischemia in Patients with Aneurysmal Subarachnoid Hemorrhage

OBJECTIVE To detect cerebral autoregulation (CA) in patients with aneurysmal subarachnoid hemorrhage (aSAH) by near-infrared spectroscopy and to assess its association with delayed cerebral ischemia (DCI). METHODS From January to August 2017, 81 patients (average age 53.25 ± 10.27 years) were studied. Near-infrared spectroscopy was used to monitor CA, and associated factors were evaluated. Monitoring of CA was carried out at 5 time points (preoperative day 1 and postoperative days 1, 2, 3, and 7). Patients were sorted into 2 groups according to whether DCI occurred (DCI group and non-DCI group). The relationship between CA and DCI in patients with aSAH was analyzed. RESULTS Among 81 patients, CA trended toward being impaired in patients with aSAH with a poorer grade. DCI occurred in 39 of 51 (48.15%) patients with impaired CA. DCI occurred in 6 of 30 (7.4%) patients with intact CA. CONCLUSIONS Impaired CA monitored by near-infrared spectroscopy was shown in patients with aSAH before and after surgical intervention. Older age, smoking, hypertension, and especially impaired CA are independent risk factors for patients with DCI.

Objective evaluation of the treatment methods of intracranial aneurysm surgery.

OBJECTIVE this study evaluated the clinical value of craniotomy and intravascular embotherapy in the treatment of intracranial aneurysms. METHODS The clinical data of 126 cases of intracranial aneurysms from July 2008 to July 2009 was analyzed retrospectively, 86 cases of all were clipped and other 40 cases were coiled. RESULTS in 86 cases with craniotomy (according to Hunt-Hess classification, 71 cases belong to grade I-III and 15 cases belong to grade IV-V), 1 case died, 3 cases recovered with serious nervous system symptoms, 9 cases recovered with Mild neurological symptoms, and the remaining 73 cases recovered with normal life and work. In 40 cases with intravascular embotherapy (according to Hunt-Hess classification, 33 cases belong to grade I-III and 7 cases belong to grade IV-V), 2 cases recovered with serious nervous system symptoms, 5 cases recovered with mild neurological symptoms, the remaining 33 cases recovered with normal life and work; no death case. CONCLUSIONS the situation is different in patients according to aneurysm size, shape, and location; if treatment for intracranial aneurysms is to achieve a satisfactory effect, two treatments must complement each other.