The lncRNA-AK046375 Upregulates Metallothionein-2 by Sequestering miR-491-5p to Relieve the Brain Oxidative Stress Burden after Traumatic Brain Injury.

We previously discovered that traumatic brain injury (TBI) induces significant perturbations in long noncoding RNA (lncRNA) levels in the mouse cerebral cortex, and lncRNA-AK046375 is one of the most significantly changed lncRNAs after TBI. lncRNA-AK046375 overexpression and knockdown models were successfully constructed both in vitro and in vivo. In cultured primary cortical neurons and astrocytes, lncRNA-AK046375 sequestered miR-491-5p, thereby enhancing the expression of metallothionein-2 (MT2), which ameliorated oxidative-induced cell injury. In addition, upregulated lncRNA-AK046375 promoted the recovery of motor, learning, and memory functions after TBI in C57BL/6 mice, and the underlying mechanism may be related to ameliorated apoptosis, inhibited oxidative stress, reduced brain edema, and relieved loss of tight junction proteins at the blood-brain barrier in the mouse brain. Therefore, we conclude that lncRNA-AK046375 enhances MT2 expression by sequestering miR-491-5p, ultimately strengthening antioxidant activity, which ameliorates neurological deficits post-TBI.

Downregulation of miR-491-5p promotes neovascularization after traumatic brain injury.

MicroRNA-491-5p (miR-491-5p) plays an important role in regulating cell proliferation and migration; however, the effect of miR-491-5p on neovascularization after traumatic brain injury remains poorly understood. In this study, a controlled cortical injury model in C57BL/6 mice and an oxygen-glucose deprivation model in microvascular endothelial cells derived from mouse brain were established to simulate traumatic brain injury in vivo and in vitro, respectively. In the in vivo model, quantitative real-time-polymerase chain reaction results showed that the expression of miR-491-5p increased or decreased following the intracerebroventricular injection of an miR-491-5p agomir or antagomir, respectively, and the expression of miR-491-5p decreased slightly after traumatic brain injury. To detect the neuroprotective effects of miR-491-p, neurological severity scores, Morris water maze test, laser speckle techniques, and immunofluorescence staining were assessed, and the results revealed that miR-491-5p downregulation alleviated neurological dysfunction, promoted the recovery of regional cerebral blood flow, increased the number of lectin-stained microvessels, and increased the survival of neurons after traumatic brain injury. During the in vitro experiments, the potential mechanism of miR-491-5p on neovascularization was explored through quantitative real-time-polymerase chain reaction, which showed that miR-491-5p expression increased or decreased in brain microvascular endothelial cells after transfection with an miR-491-5p mimic or inhibitor, respectively. Dual-luciferase reporter and western blot assays verified that metallothionein-2 was a target gene for miR-491-5p. Cell counting kit 8 (CCK-8) assay, flow cytometry, and 2?,7?-dichlorofluorescein diacetate (DCFH-DA) assay results confirmed that the downregulation of miR-491-5p increased brain microvascular endothelial cell viability, reduced cell apoptosis, and alleviated oxidative stress under oxygen-glucose deprivation conditions. Cell scratch assay, Transwell assay, tube formation assay, and western blot assay results demonstrated that miR-491-5p downregulation promoted the migration, proliferation, and tube formation of brain microvascular endothelial cells through a metallothionein-2-dependent hypoxia-inducible factor-1α/vascular endothelial growth factor pathway. These findings confirmed that miR-491-5p downregulation promotes neovascularization, restores cerebral blood flow, and improves the recovery of neurological function after traumatic brain injury. The mechanism may be mediated through a metallothionein-2-dependent hypoxia-inducible factor-1α/vascular endothelial growth factor signaling pathway and the alleviation of oxidative stress. All procedures were approved by Ethics Committee of the First Affiliated Hospital of Chongqing Medical University, China (approval No. 2020-304) on June 22, 2020.

Neat1 decreases neuronal apoptosis after oxygen and glucose deprivation.

Studies have shown that downregulation of nuclear-enriched autosomal transcript 1 (Neat1) may adversely affect the recovery of nerve function and the increased loss of hippocampal neurons in mice. Whether Neat1 has protective or inhibitory effects on neuronal cell apoptosis after secondary brain injury remains unclear. Therefore, the effects of Neat1 on neuronal apoptosis were observed. C57BL/6 primary neurons were obtained from the cortices of newborn mice and cultured in vitro, and an oxygen and glucose deprivation cell model was established to simulate the secondary brain injury that occurs after traumatic brain injury in vitro. The level of Neat1 expression in neuronal cells was regulated by constructing a recombinant adenovirus to infect neurons, and the effects of Neat1 expression on neuronal apoptosis after oxygen and glucose deprivation were observed. The experiment was divided into four groups: the control group, without any treatment, received normal culture; the oxygen and glucose deprivation group were subjected to the oxygen and glucose deprivation model protocol; the Neat1 overexpression and Neat1 downregulation groups were treated with Neat1 expression intervention techniques and were subjected to the in oxygen and glucose deprivation protocol. The protein expression levels of neurons p53-induced death domain protein 1 (PIDD1, a pro-apoptotic protein), caspase-2 (an apoptotic priming protein), cytochrome C (a pro-apoptotic protein), and cleaved caspase-3 (an apoptotic executive protein) were measured in each group using the western blot assay. To observe changes in the intracellular distribution of cytochrome C, the expression levels of cytochrome C in the cytoplasm and mitochondria of neurons from each group were detected by western blot assay. Differences in the cell viability and apoptosis rate between groups were detected by cell-counting kit 8 assay and terminal deoxynucleotidyl transferase dUTP nick-end labeling assay, respectively. The results showed that the apoptosis rate, PIDD1, caspase-2, and cleaved caspase-3 expression levels significantly decreased, and cell viability significantly improved in the Neat1 overexpression group compared with the oxygen and glucose deprivation group; however, Neat1 downregulation reversed these changes. Compared with the Neat1 downregulation group, the cytosolic cytochrome C level in the Neat1 overexpression group significantly decreased, and the mitochondrial cytochrome C level significantly increased. These data indicate that Neat1 upregulation can reduce the release of cytochrome C from the mitochondria to the cytoplasm by inhibiting the PIDD1-caspase-2 pathway, reducing the activation of caspase-3, and preventing neuronal apoptosis after oxygen and glucose deprivation, which might reduce secondary brain injury after traumatic brain injury. All experiments were approved by the Animal Ethics Committee of the First Affiliated Hospital of Chongqing Medical University, China, on December 19, 2020 (approval No. 2020-895).

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.

Clinical and Basic Evaluation of the Prognostic Value of Uric Acid in Traumatic Brain Injury.

Background: As a major antioxidant in serum, uric acid (UA) was once considered only as the leading cause of gout; however, recent studies have validated its neuroprotective role in ischemic stroke. Because the potential protective effects of UA in traumatic brain injury (TBI) remain largely unknown, this study investigated the role of UA in TBI in both clinical patients and experimental animals. Methods: In TBI patients, serum UA concentrations were measured within 3 days after injury. Clinical outcomes at discharge were classified according to the Glasgow Outcome Scale: good outcome (4-5) and poor outcome (1-3). Risk factors for good outcome were identified via backward logistic regression analysis. For the animal study, a controlled cortical impact (CCI) injury model was established in mice. These mice were given UA at different doses intraperitoneally, and subsequent UA concentrations in mouse serum and brain tissue were determined. Neurological function, oxidative stress, inflammatory response, neuronal maintenance, cerebral blood flow, and lesion size were also assessed. Results: The serum UA level was significantly lower in TBI patients who had a good outcome (P<0.01), and low serum UA was an independent predictor of good outcome after TBI (P<0.01; odds ratio, 0.023; 95% confidence interval, 0.006-0.082). Consistently, decreased levels of serum UA were observed in both TBI patients and CCI animals (P<0.05), whereas the UA concentration was increased in CCI brain tissue (P<0.05). Administration of UA further increased the UA level in brain tissue as compared to that in control animals (P<0.05). Among the different doses administered, 16 mg/kg UA improved sensorimotor functional recovery, spatial learning, and memory in CCI mice (P<0.05). Moreover, oxidative stress and the inflammatory response were inhibited by UA treatment (P<0.05). UA treatment also improved neuronal maintenance and cortical blood flow (P<0.05) but not lesion size (P>0.05). Conclusions: UA acted to attenuate neuronal loss, cerebral perfusion impairment and neurological deficits in TBI mice through suppression of neuronal and vascular oxidative stress. Following TBI, active antioxidant defense in the brain may result in consumption of UA in the serum, and thus, a decreased serum UA level could be predictive of good clinical recovery.

Human heart failure biomarker immunosensor based on excessively tilted fiber gratings.

A label-free immunosensor platform based on excessively tilted fiber gratings (Ex-TFGs) was developed for highly specific and fast detection of human N-terminal pro-B-type natriuretic peptide (NT-proBNP), which is considered a powerful biomarker for prognosis and risk stratification of heart failure (HF). High-purity anti-NT-proBNP monoclonal antibodies (MAbs) prepared in our laboratory were immobilized on fiber surface through the staphylococcal protein A (SPA) method for subsequent specific binding of the targeted NT-proBNP. Utilizing fiber optic grating demodulation system (FOGDS), immunoassays were carried out in vitro by monitoring the resonance wavelength shift of Ex-TFG biosensor with immobilized anti-NT-proBNP MAbs. Lowest detectable concentration of ~0.5ng/mL for NT-proBNP was obtained, and average sensitivity for NT-proBNP at a concentration range of 0~1.0 ng/mL was approximately 45.967 pm/(ng/mL). Several human serum samples were assessed by the proposed Ex-TFG biomarker sensor, with high specificity for NT-proBNP, indicating potential application in early diagnosing patients with acute HF symptoms.

Clinical study of changes of cerebral microcirculation in cerebral vasospasm after SAH.

Aim to investigate the changes of cerebral microcirculation after subarachnoid hemorrhage (SAH) and its association with cerebral vasospasm (CVS) after SAH. CTP was performed in 85 patients with SAH and 35 controls. Cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) were recorded for final analysis. CTP parameters were compared between (1) SAH group and control group, (2) CVS group and non-CVS group (nCVS), (3) symptomatic CVS (sCVS) group and asymptomatic CVS (asCVS) group. Compared to control group, there were significant differences in CBF and MTT of SAH patients (P<0.05). Among SAH patients, the CBF and MTT (a decreased CBF and a prolonged MTT) of CVS patients were significantly different from those of non-CVS patients (P<0.05). In 46 CVS patients, sCVS group presented significantly lower CBF and more prolonged MTT than asCVS patients (P<0.05). Seven cases with MTT between 6.31 and 12.72 s showed delayed ischemic neurological deficit (DIND), two of whom had hemiplegia, and one died. Our findings suggest that CTP examination contributes to uncover the changes of cerebral microcirculation after SAH, and the changes of cerebral microcirculation are associated with CVS post SAH.

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.