Effects of plaque characteristics and artery hemodynamics on the residual stenosis after carotid artery stenting.

OBJECTIVE: Carotid artery stenting (CAS) has become an alternative strategy to carotid endarterectomy for carotid artery stenosis. Residual stenosis was an independent risk factor for restenosis, with the latter affecting the long-term outcomes of CAS. This multicenter study aimed to evaluate the echogenicity of plaques and hemodynamic alteration by color duplex ultrasound (CDU) examination and investigate their effects on the residual stenosis after CAS. METHODS: From June 2018 to June 2020, 454 patients (386 males and 68 females) with a mean age of 67.2 ± 7.9 years, who underwent CAS from 11 advanced stroke centers in China were enrolled. One week before recanalization, CDU was used to evaluate the responsible plaques, including the morphology (regular or irregular), echogenicity of the plaques (iso-, hypo-, or hyperechoic) and calcification characteristics (without calcification, superficial calcification, inner calcification, and basal calcification). One week after CAS, the alteration of diameter and hemodynamic parameters were evaluated by CDU, and the occurrence and degree of residual stenosis were determined. In addition, magnetic resonance imaging was performed before and during the 30-day postprocedural period to identify new ischemic cerebral lesions. RESULTS: The rate of composite complications, including cerebral hemorrhage, symptomatic new ischemic cerebral lesions, and death after CAS, was 1.54% (7/454 cases). The rate of residual stenosis after CAS was 16.3% (74/454 cases). After CAS, both the diameter and peak systolic velocity (PSV) improved in the preprocedural 50% to 69% and 70% to 99% stenosis groups (P < .05). Compared with the groups without residual stenosis and with <50% residual stenosis, the PSV of all three segments of stent in the 50% to 69% residual stenosis group were the highest, and the difference in the midsegment of stent PSV was the largest (P < .05). Logistic regression analysis showed that preprocedural severe (70% to 99%) stenosis (odds ratio [OR], 9.421; P = .032), hyperechoic plaques (OR, 3.060; P = .006) and plaques with basal calcification (OR, 1.885; P = .049) were independent risk factors for residual stenosis after CAS. CONCLUSIONS: Patients with hyperechoic and calcified plaques of the carotid stenosis are at a high risk of residual stenosis after CAS. CDU is an optimal, simple and noninvasive imaging method to evaluate plaque echogenicity and hemodynamic alterations during the perioperative period of CAS, which can help surgeons to select the optimal strategies and prevent the occurrence of residual stenosis.

Synergistic Interaction Between Zinc and Reactive Oxygen Species Amplifies Ischemic Brain Injury in Rats.

Background and Purpose- Although intracellular zinc accumulation has been shown to contribute to neuronal death after cerebral ischemia, the mechanism by which zinc keeps on accumulating to cause severe brain damage remains unclear. Herein the dynamic cause-effect relationships between zinc accumulation and reactive oxygen species (ROS) production during cerebral ischemia/reperfusion are investigated. Methods- Rats were treated with zinc chelator, ROS scavenger, mitochondria-targeted ROS inhibitor, or NADPH oxidase inhibitor during a 90-minute middle cerebral artery occlusion. Cytosolic labile zinc, ROS level, cerebral infarct volume, and neurological functions were assessed after ischemia/reperfusion. Results- Zinc and ROS were colocalized in neurons, leading to neuronal apoptotic death. Chelating zinc reduced ROS production at 6 and 24 hours after reperfusion, whereas eliminating ROS reduced zinc accumulation only at 24 hours. Furthermore, suppression of mitochondrial ROS production reduced the total ROS level and brain damage at 6 hours after reperfusion but did not change zinc accumulation, indicating that ROS is produced mainly from mitochondria during early reperfusion and the initial zinc release is upstream of ROS generation after ischemia. Suppression of NADPH oxidase decreased ROS generation, zinc accumulation, and brain damage only at 24 hours after reperfusion, indicating that the majority of ROS is produced by NADPH oxidase at later reperfusion time. Conclusions- This study provides the direct evidence that there exists a positive feedback loop between zinc accumulation and NADPH oxidase-induced ROS production, which greatly amplifies the damaging effects of both. These findings reveal that different ROS-generating source contributes to ischemia-generated ROS at different time, underscoring the critical importance of spatial and temporal factors in the interaction between ROS and zinc accumulation, and the consequent brain injury, after cerebral ischemia/reperfusion.

Chrysophanol attenuates nitrosative/oxidative stress injury in a mouse model of focal cerebral ischemia/reperfusion.

Nitrosative/oxidative stress plays an important role in neuronal death following cerebral ischemia/reperfusion (I/R). Chrysophanol (CHR) has been shown to afford significant neuroprotection on ischemic stroke, however, whether its mechanism is related to attenuating nitrosative/oxidative stress is not clear. In the present study, we investigated the effect of CHR on neuronal injury related to nitric oxide (NO) production by using mouse middle cerebral artery occlusion (MCAO) model. Our results revealed that nitrite plus nitrate (NOx-) and 3-nitrotyrosine (3-NT) levels increased in ischemic brain 14 days after reperfusion, and were subsequently attenuated by CHR treatment. Moreover, 3-NT is colocalized with NeuN and TUNEL, suggesting that neuronal apoptosis following I/R is associated with 3-NT and CHR suppresses NO-associated neuronal cell death. Accordingly, cleaved caspase-3 expression in ischemic brain was decreased by CHR treatment. I/R also decreased the activity of total superoxide dismutase (SOD) and manganese-dependent SOD (MnSOD), whilst increased reactive oxygen species (ROS) production significantly. Interestingly, CHR reversed this decrease in total SOD, and MnSOD activity, and inhibited ROS generation in the ischemic brain. Taken together, our results provide direct evidence suggesting that CHR attenuates nitrosative/oxidative stress injury induced by I/R, providing a novel therapeutic target in the treatment of acute ischemic stroke.

Assessment of neurologists' knowledge regarding intravenous fibrinolytic therapy for acute stroke in Shanxi province in China.

BACKGROUND: Limitations in physicians' knowledge regarding fibrinolytic therapy for acute ischemic stroke may contribute to low rate of fibrinolytic therapy in China. Here physicians' knowledge was surveyed on intravenous fibrinolytic therapy for acute ischemic stroke. METHODS: Neurologists (n = 175) from 27 major general hospitals in Shanxi province, P. R. China, were invited to complete questionnaires regarding their basic knowledge of intravenous fibrinolytic therapy for acute ischemic stroke. The questionnaire contained 12 multiple-choice questions. One point was assigned for a correct answer and zero point for a false or unanswered question. RESULTS: One hundred and thirty-one neurologists (74.9%) responded to the questionnaires. The mean accuracy rate of 12 questions was 54.9 ± 25.01% (range 0.8-96.2%). The mean total score for respondents was 6.59 ± 2.03 (range 2-11). More years of experience and higher academic degrees were independent factors related to the total scores (P = 0.000 and P = 0.004, respectively). CONCLUSIONS: The neurologists in this study were knowledge deficient in the area of intravenous fibrinolytic therapy for acute ischemic stroke. This partially accounts for the low rate of fibrinolytic therapy in China.

Nomogram to Predict Cognitive Impairment in Patients with Asymptomatic Middle Cerebral Artery Stenosis.

Purpose: This study aims to investigate the characteristics and influencing factors of cognitive impairment in patients with asymptomatic middle cerebral artery stenosis (aMCAS) and to construct a nomogram to predict the risk of cognitive impairment in patients with aMCAS. Patients and Methods: We collected 54 patients with aMCAS and 35 healthy controls to investigate the impaired cognitive domains and pathogenesis in patients with aMCAS. All patients underwent a cranial MRI, CT perfusion, transcranial Doppler ultrasound, blood tests, and a comprehensive neuropsychological evaluation. According to the MoCA score, patients were divided into cognitively normal and cognitively impaired groups. To construct the nomogram, we conducted univariate and multivariate logistic regression analyses to identify factors that affect cognitive function. And the performance of nomogram was evaluated by ROC curves, calibration curves, decision curve analysis (DCA), and clinical impact curve (CIC). Results: In 54 patients with aMCAS, 24 patients presented with cognitive normal, and 30 patients presented with cognitive impairment. The results of multivariate logistic regression suggested that perfusion decompensation, middle cerebral artery mean flow velocity, and LDL-cholesterol levels were independent influencing factors of cognitive impairment. In the following step, a nomogram was constructed. The AUC of the nomogram is 0.862. Calibrating curves show good agreement between nomogram predictions and actual observations, while DCA and CIC show great clinical usefulness. Conclusion: Patients with aMCAS have cognitive impairment in multiple cognitive domains, and impaired executive function was observed during the perfusion compensation period. Furthermore, a nomogram was constructed and validated to predict the risk of cognitive impairment in patients with aMCAS, which can help clinicians to identify at an early stage and improve the management of patients.

Nitric oxide promotes cerebral ischemia/reperfusion injury through upregulating hypoxia-inducible factor1-α-associated inflammation and apoptosis in rats.

Nitric oxide (NO) was one of the key factors to sustain hypoxia-inducible factor-1- α (HIF-1α) activation during hypoxia. However, the mechanism by which NO production promotes upregulation of HIF-1α to cause cerebral ischemia/reperfusion (I/R) injury remains unclear. The present study investigated whether eliminating NO would decrease HIF-1α level, and then reduce the subsequent inflammatory actions as well as neuronal apoptotic death in middle cerebral artery occlusion (MCAO) rats. Our results revealed that HIF-1α was correlated with 3-NT, a marker for nitrosative/oxidative stress, in the brain of MCAO rats. Treatment with NOS inhibitor L-NAME suppressed HIF-1α/3-NT double-positive cells, suggesting that HIF-1α was correlated with NO overproduction during cerebral I/R. Furthermore, pro-inflammatory cytokines TNF-α, IL-1ß and NF-κB p65 were significantly increased and colocalized with HIF-1α in the brain of MCAO rats, all of which could be attenuated by NO inhibition, suggesting that eliminating NO reduced MCAO-induced HIF-1α upregulation, which in turn exerted anti-inflammatory actions. Accordingly, cleaved caspase-3, as well as HIF-1α and TUNEL double-positive cells in ischemic brain were also decreased by L-NAME treatment. These results suggest that NO accumulation after cerebral ischemia leads to HIF-1α upregulation, which may activate pro-inflammatory cytokines, resulting in neuronal apoptotic death. These findings demonstrate a novel mechanism of NO-induced cerebral I/R injury.

Inhibition of the JAK2/STAT3 pathway and cell cycle re-entry contribute to the protective effect of remote ischemic pre-conditioning of rat hindlimbs on cerebral ischemia/reperfusion injury.

AIMS: Remote ischemic pre-conditioning (RIPC) protects against ischemia/reperfusion (I/R) injury. However, the mechanisms underlying this protection remain unclear. In the present study, we investigated the role of Janus-activated kinase 2 (JAK2)/signal transducer and activator of transcription 3 (STAT3) pathway and cell cycle arrest, and their relationship with neuronal apoptosis following RIPC. METHODS: A rat cerebral I/R injury model was induced by middle cerebral artery occlusion (MCAO), and AG490 was used to investigate the mechanisms of RIPC. p-JAK2-, p-STAT3-, cyclin D1-, and cyclin-dependent kinase 6 (CDK6) expression was assessed by Western blotting and immunofluorescence staining. RESULTS: RIPC reduced the infarct volume, improved neurological function, and increased neuronal survival. Furthermore, p-JAK2 and p-STAT3 were detected during the initial phase of reperfusion; the expression levels were significantly increased at 3 and 24 h after reperfusion and were suppressed by RIPC. Additionally, the MCAO-induced upregulation of the cell cycle regulators cyclin D1 and CDK6 was ameliorated by RIPC. Meanwhile, cyclin D1 and CDK6 were colocalized with p-STAT3 in the ischemic brain. CONCLUSION: RIPC ameliorates the induction of the JAK2/STAT3 pathway and cell cycle regulators cyclin D1 and CDK6 by MCAO, and this net inhibition of cell cycle re-entry by RIPC is associated with downregulation of STAT3 phosphorylation.

Corrigendum: Factors affecting physician decision-making regarding antiplatelet therapy in minor ischemic stroke.

[This corrects the article DOI: 10.3389/fneur.2022.937417.].

Factors affecting physician decision-making regarding antiplatelet therapy in minor ischemic stroke.

Purpose: To identify the most important factors affecting physician decision-making regarding antiplatelet therapy. Methods: We retrospectively gathered data from minor ischemic stroke patients with NIHSS scores ≤ 5 within 72 h of onset from 2010 to 2018. The population was divided into four groups by initial antiplatelet therapy: aspirin monotherapy (AM), dual antiplatelet therapy with aspirin and a loading dose of clopidogrel (clopidogrel loading dose of 300 mg on the first day; DAPT-ALC), dual antiplatelet therapy with aspirin and no loading dose of clopidogrel (clopidogrel 75 mg daily, no loading dose; DAPT-AUC), and clopidogrel monotherapy (CM). Results: In total, 1,377 patients were included in the analysis (excluding patients who accepted thrombolytic drugs, participated in other clinical trials, or had not used antiplatelet drugs). The mean ± S.D. age was 62.0 ± 12.7 years; 973 (70.7%) patients were male. The four groups were AM (n = 541, 39.3%), DAPT-ALC (n = 474, 34.4%), DAPT- AUC (n = 301, 21.9%), and CM (n = 61, 4.4%). Patients receiving antiplatelet monotherapy were older than those receiving dual antiplatelet therapy (63.7-65.7 vs. 59.6-61.4 years), and the median initial systolic blood pressure level was higher in the DAPT-ALC group than in the other groups (all P < 0.05). Patients under 75 years old with an admission SBP lower than 180 mmHg, a history of AM, coronary heart disease, no history of intracerebral hemorrhage, stroke onset occurring after guideline recommendations were updated (the year of 2015), onset-to-arrival time within 24 h, and initial NIHSS score ≤ 3 were more likely to take DAPT-ALC than AM. Compared with DAPT-ALC, DAPT-AUC was associated with an initial SBP level lower than 180 mmHg, a history of smoking, hypertension, no history of ICH, previous treatment with antihypertensives, and onset year after the recommendations were updated. Conclusions: Many factors affect doctors' decisions regarding antiplatelet therapy, especially guidelines, age, admission SBP level, and hypertensive disease.

A nomogram for predicting the in-hospital risk of recurrence among patients with minor non-cardiac stroke.

BACKGROUND: Patients with minor stroke suffer a substantial risk of further recurrences, especially in the first two weeks. We aimed to develop and validate a prognostic nomogram to predict in-hospital stroke recurrence among patients with acute minor stroke. METHODS: A total of 1326 patients with minor non-cardiac stroke (NIHSS) ≤5) from three centers were divided into development cohort (1016 patients from two centers) and validation cohort (310 patients from another center). Recurrent stroke was defined as a new ischemic stroke. A logistic regression model was employed to develop the nomogram to predict in-hospital stroke recurrence in patients with minor stroke using demographic, medical and imaging information. We then validated the nomogram externally. The predictive discrimination and calibration of the nomogram were assessed in the development and validation cohorts by area under the curve (AUC) and calibration plots. RESULTS: During a median length of stay of 12 days, stroke recurrence occurred in 34 patients (3.3%). Predictors of in-hospital recurrence included prior history of transient ischemic attack, baseline NIHSS score, multiple infarctions, and carotid stenosis. The clinical and imaging-based nomogram B demonstrated adequate calibration and discrimination (AUC = 0.777), which was validated among 273 patients in a separate validation cohort (AUC = 0.753). Our clinical-imaging based nomogram was determined to be superior to the clinical-based nomogram and the RRE90 score in terms of discrimination. CONCLUSION: A prognostic nomogram that integrates clinical and imaging information to predict the in-hospital risk of stroke recurrence among patients after acute minor stroke was constructed and validated externally. The nomogram demonstrated adequate calibration and discrimination in both the development and validation cohort.

Comparison of the Characteristics and Risk Factors of Carotid Atherosclerosis in High Stroke Risk Populations Between Urban and Rural Areas in North China.

Objective: To study the characteristics and risk factors of carotid atherosclerosis in populations at high risk of stroke in urban and rural areas of North China. Methods: A cross-sectional study was conducted to investigate high stroke risk populations in representative urban and rural areas sampled from 12 regions of China. A pre-designed questionnaire, ultrasound, and laboratory examinations were performed to evaluate risk factors. Results: A total of 30,175 patients were included in the study. The overall prevalence of carotid atherosclerosis was 54.53%, among which intimal thickening and plaque were 39.22 and 41.25%, respectively. The prevalence of carotid atherosclerosis in the urban group was higher than in the rural group. Multivariate logistic regression analysis revealed that male gender, age, smoking, hypertension, dyslipidemia, stroke, atrial fibrillation, systolic blood pressure, and levels of fasting blood glucose, total cholesterol, and low-density lipoprotein cholesterol were the common independent risk factors for carotid atherosclerosis in both groups. Higher education, high salt consumption, passive smoking, family history of stroke, and transient ischemic attack were unique independent risk factors, and high-density lipoprotein cholesterol was a protective factor for carotid atherosclerosis in the urban population. Conclusion: This study suggests that risk factors for carotid atherosclerosis differ between urban and rural populations in North China.

Distribution Pattern of Atherosclerotic Stenosis in Chinese Patients with Stroke: A Multicenter Registry Study.

The aim of this multicenter study was to demonstrate the distribution pattern of atherosclerotic stenosis and its trend with aging between extracranial and intracranial arteries and its distribution between the anterior and posterior circulations in Chinese patients hospitalized with ischemic stroke. In addition, the risk factors for the distribution pattern were illustrated. From June 2015 to May 2016, 9,346 patients with ischemic stroke from 20 hospitals were enrolled. Carotid artery ultrasonography and transcranial color-coded sonography/transcranial Doppler were used to evaluate the extracranial and intracranial arteries. The distribution pattern of atherosclerotic stenosis and its trend with aging were analyzed. Logistic regression was used to analyze the risk factors for the distribution pattern. Among the 9,346 patients, 2,882 patients (30.8%) had at least one artery with a degree of stenosis ≥50%. Among patients with arterial stenosis, the proportion of patients with intracranial artery stenosis was higher than those with extracranial artery stenosis (52.6% vs. 27.6%), and the proportion of anterior circulation artery stenosis was higher than that in the posterior circulation (52.2% vs.26.2%). With aging, the proportion of intracranial artery stenosis alone decreased; at the same time, the proportion of extracranial artery stenosis and extracranial plus intracranial artery stenosis increased (trend χ2=6.698, P=0.001). Hypertension (OR 1.416, P=0.008) and family history of stroke (OR 1.479, P=0.014) were risk factors for intracranial artery stenosis. Male, aging, and smoking were factors more related to extracranial artery stenosis. Aging (OR 1.022, P<0.001) and hypertension (OR 1.392, P=0.019) were related to posterior circulation artery stenosis. Intracranial arteries and anterior circulation arteries were susceptible to stenosis in Chinese patients with ischemic stroke. However, the distribution pattern of atherosclerotic stenosis was dynamic and varied with aging. Aging and different risk factors contribute to this distribution pattern.

Chrysophanol inhibits endoplasmic reticulum stress in cerebral ischemia and reperfusion mice.

Endoplasmic reticulum (ER) stress plays a critical role in mediating ischemia/reperfusion (I/R) damage in the brain. Our previous study showed that Chrysophanol (CHR) alleviated cerebral ischemic injury in mice and nuclear factor-κB (NF-κB) involved in its neuroprotective effect, but the precise mechanism remains not fully understood. The present study investigated the effect of CHR treatment on I/R-induced ER stress. Mice were subjected to middle cerebral artery occlusion (MCAO) for 45min and received either vehicle or CHR (0.1mg/kg) for 14 days after reperfusion. Terminal deoxynucleotidyl transferase (TdT)-mediated dUTP nick end labeling (TUNEL) was used to detect apoptotic cells in penumbral tissue. The expression of ER stress-related factors including glucose-regulated protein 78 (GRP78), phosphorylated eukaryotic initiation factor 2α (p-eIF2α), CCAAT-enhancer-binding protein homologous protein (CHOP), and caspase-12 as well as inhibitory κB-α (IκB-α), the inhibitor of NF-κB, was assessed. Our results demonstrated that CHR treatment reduced MCAO-induced upregulation of GRP78, p-eIF2α, CHOP, and caspase-12 in the ischemic brain. Moreover, the TUNEL-positive neuronal cells, which were colocalized with CHOP and caspase-12, decreased in response to CHR treatment, indicating that CHR protects against I/R injury by inhibiting ER stress-associated neuronal apoptosis. In addition, CHR reversed the decrease in IκB-α level induced by MCAO, which was attributed at least in part to the attenuation of translational inhibition induced by eIF2α phosphorylation, indicating that CHR exerts anti-inflammatory effects following I/R by inhibiting ER stress response. These results suggest that attenuation of ER stress may be involved in the mechanisms of neuroprotective effects of CHR.

No association between elevated homocysteine levels and carotid atherosclerosis in a rural population in China.

OBJECTIVES: We wish to determine if homocysteine (Hcy) is an independent risk factor for carotid atherosclerosis in a rural Chinese population. METHODS: 2291 individuals (1016 men and 1275 women), aged 64.6±7.4 years, from Lvliang, China participated in this study. Tests performed included carotid artery ultrasound scan and blood analysis, to measure Hcy levels and other blood components. RESULTS: The mean serum Hcy level was 24.7±18.0 µmol/L. The overall detection rate of carotid atherosclerotic lesions was 76.3% and the detection rate of plaque was 48.6%. Participants were divided into 4 groups based on their Hcy levels, <14.49, 14.49-19.43, 19.44-28.30, and ≥28.30 µmol/L. The relative risk of carotid atherosclerosis for each quartile as compared with the risk for the lowest quartile was estimated as the OR derived from the logistic regression coefficients. After adjusting for age and gender, the OR of carotid atherosclerosis in the third and fourth quartiles of Hcy were 1.219 (95% CI 0.922 to 1.612) and 1.156 (95% CI 0.859 to 1.555; p>0.05), respectively. After controlling for demographic variables (age, gender, current smoker, fasting blood glucose, low-density lipoprotein and systolic blood pressure) the OR of carotid plaque(s) in the third and fourth quartiles were 1.246 (95% CI 0.967 to 1.606) and 1.259 (95% CI 0.963 to 1.646; p>0.05). CONCLUSIONS: The mean value of Hcy among participants in this study was much higher than that previously reported. However, no significant correlation between elevated Hcy and carotid atherosclerosis was found.

Neuroprotective effects of Chrysophanol against inflammation in middle cerebral artery occlusion mice.

Ischemia/reperfusion (I/R) involves a cascade of reactions which ultimately lead to neuronal apoptosis or death. Inflammation plays an important role in this cascade. Chrysophanol (CHR), a purified active constituent from rhubarb, possesses many biological activities including anti-inflammation. The present study investigated the long-term neuroprotective effects of CHR on focal ischemic brain injury and the potential mechanism. Mice were subjected to 45-min middle cerebral artery occlusion and received either vehicle or CHR at 0.1, 1 or 10mg/kg for 14days after reperfusion. Neurological function, survival rate, brain tissue loss, expression of pro-inflammatory factors tumor necrosis factor-α (TNF-α), interleukin-1ß (IL-1ß) and nuclear factor-kappa B p65 (NF-κB p65) were then assessed. The results showed that treatment with CHR led to improved survival rate and reduced brain tissue loss compared with vehicle-treated mice, accompanied by improved neurological assessment and motor function, which were sustained for 14days after I/R. I/R-induced expression of TNF-α, IL-1ß and NF-κB p65 in neurons was markedly reduced in CHR-treated mice. These results indicate that CHR markedly attenuates brain injury after focal I/R, which is attributed at least in part to its anti-inflammatory actions.

Comparison of polyhydroxyalkanoates production by activated sludges from anaerobic and oxic zones of an enhanced biological phosphorus removal system: effect of sludge retention time.

This study compared the PHAs production behavior of sludges from the anaerobic and oxic phases of an enhanced biological phosphorus removal (EBPR) system. This was accomplished by using the kinetics and stoichiometric coefficients obtained from aerobic batch tests to evaluate the performance of these two sludges. Experimental results indicated that the metabolic behavior of the sludges for PHAs production depend significantly on the operating sludge retention time (SRT) of the EBPR system. The oxic sludge with 5 days of SRT exhibited better PHAs production performance than anaerobic sludge. Conversely, the anaerobic sludge with 15 days of SRT had superior PHAs production capability compared to oxic sludge. These comparisons suggest that whether anaerobic or oxic sludge should be employed for PHAs production depends mainly on the operating SRT of the EBPR system.