Hyperglycemia is associated with more severe cytotoxic injury after stroke

Validation of a Novel Magnetic Resonance Imaging Biomarker of Infarct Severity to Predict Functional Outcome After Endovascular Thrombectomy

BACKGROUND

Endovascular thrombectomy (EVT) dramatically improves clinical outcomes, but the final infarct volume (FIV) on magnetic resonance imaging only accounts for a minority of the treatment effect. An imaging biomarker that more strongly correlates with post-EVT functional outcome would be helpful for clinical prognosis and serve as a surrogate outcome measure in trials of EVT-adjuvant therapies. Here, we aimed to validate a novel magnetic resonance imaging-based metric, infarct density, which leverages post-EVT apparent diffusion coefficient as a marker of infarct severity.

METHODS

A retrospective cohort was derived from a single-center prospective EVT registry. Consecutive patients treated with EVT for anterior circulation large vessel occlusion were included from 2018 to 2019 who achieved successful reperfusion (modified Thrombolysis in Cerebral Infarction ≥2b). Magnetic resonance imaging was performed 12 to 48 hours post-EVT and processed via RAPID to quantify FIV using the apparent diffusion coefficient <620 threshold. Lesion volume was also collected using an apparent diffusion coefficient <470 threshold, and infarct density was calculated as: (volume <470/volume <620)×100%. Good outcome was defined as ≤2 on the 90-day modified Rankin Scale. Multivariable logistic regression models quantified the association between clinical/imaging variables and outcome. Receiver operating characteristic analysis quantified model classification performance.

RESULTS

Of 319 patients treated with EVT, 272 met inclusion criteria. The mean age was 69±13 years, 41% were female, and 62% achieved a good outcome. After adjusting for clinical and radiographic factors, FIV (adjusted odds ratio, 0.99 per 1 mL [95% CI, 0.98-1.00]; P=0.03) and infarct density (adjusted odds ratio, 0.95 per 1% [95% CI, 0.94-0.97]; P<0.001) were both independently inversely associated with good outcome. The final model incorporating both FIV and infarct density achieved excellent classification performance (area under the curve, 0.87 [95% CI, 0.83-0.91]). Removing infarct density from the model diminished its performance (area under the curve, 0.83 [95% CI, 0.78-0.88]; P=0.01).

CONCLUSIONS

Apparent diffusion coefficient-based infarct density after EVT is independently associated with long-term outcome and provides greater prognostic information than FIV alone. Post-EVT infarct density may be useful in clinical care and as a surrogate outcome measure in trials of EVT-adjuvant therapies.

Infarct density defined by ADC threshold is associated with long-term functional outcome after endovascular thrombectomy

OBJECTIVES

Endovascular thrombectomy (EVT) dramatically improves clinical outcomes, but the reduction in final infarct volume only accounts for 10-15 % of the treatment benefit. We aimed to develop a novel MRI-ADC-based metric that quantify the degree of tissue injury to test the hypothesis that it outperforms infarct volume in predicting long-term outcome.

MATERIALS AND METHODS

A single-center cohort consisted of consecutive acute stroke patients with anterior circulation large vessel occlusion, successful recanalization via EVT (mTICI ≥2b), and MRI of the brain between 12 h and 7 days post-EVT. Imaging was processed via RAPID software. Final infarct volume was based on the traditional ADC <620 threshold. Logistic regression quantified the association of lesion volumes and good outcome (90-day modified Rankin Scale ≤2) at a range of lower ADC thresholds (<570, <520, and <470). Infarct density was calculated as the percentage of the final infarct volume below the ADC threshold with the greatest effect size. Univariate and multivariate logistic regression quantified the association between imaging/clinical metrics and functional outcome.

RESULTS

120 patients underwent MRI after successful EVT. Lesion volume based on the ADC threshold <470 had the strongest association with good outcome (OR: 0.81 per 10 mL; 95 % CI: 0.66-0.99). In a multivariate model, infarct density (<470/<620 * 100) was independently associated with good outcome (aOR 0.68 per 10 %; 95 % CI: 0.49-0.95), but final infarct volume was not (aOR 0.98 per 10 mL; 95 % CI: 0.85-1.14).

CONCLUSIONS

Infarct density after EVT is more strongly associated with long-term clinical outcome than infarct volume.

Acute-to-chronic glycemic ratio as an outcome predictor in ischemic stroke in patients with and without diabetes mellitus

OBJECTIVE

Elevated plasma glucose levels are common in patients suffering acute ischemic stroke (AIS), and acute hyperglycemia has been defined as an independent determinant of adverse outcomes. The impact of acute-to-chronic glycemic ratio (ACR) has been analyzed in other diseases, but its impact on AIS prognosis remains unclear. The main aim of this study was to assess whether the ACR was associated with a 3-month poor prognosis in patients with AIS.

RESEARCH, DESIGN AND METHODS

Retrospective analysis of patients admitted for AIS in Hospital del Mar, Barcelona. To estimate the chronic glucose levels (CGL) we used the formula eCGL= [28.7xHbA1c (%)]-46.7. The ACR (glycemic at admission / eCGL) was calculated for all subjects. Tertile 1 was defined as: 0.28-0.92, tertile 2: 0.92-1.13 and tertile 3: > 1.13. Poor prognosis at 3 months after stroke was defined as mRS score 3-6.

RESULTS

2.774 subjects with AIS diagnosis were included. Age, presence of diabetes, previous disability (mRS), initial severity (NIHSS) and revascularization therapy were associated with poor prognosis (p values < 0.05). For each 0.1 increase in ACR, there was a 7% increase in the risk of presenting a poor outcome. The 3rd ACR tertile was independently associated with a poor prognosis and mortality. In the ROC curves, adding the ACR variable to the classical clinical model did not increase the prediction of AIS prognosis (0.786 vs. 0.781).

CONCLUSIONS

ACR was positively associated with a poor prognosis and mortality at 3-months follow-up after AIS. Subjects included in the 3rd ACR tertile presented a higher risk of poor prognosis and mortality. Baseline glucose or ACR did not add predictive value in comparison to only using classical clinical variables.

Risk Factors and Prognosis of Early Neurological Deterioration after Bridging Therapy

BACKGROUND

Early neurological deterioration (END) after bridging therapy (BT) of acute ischemic stroke (AIS) patients is associated with poor outcomes.

OBJECTIVE

We aimed to study the incidence, risk factors and prognosis of END after BT.

METHODS

From January to December 2021, the clinical data of AIS patients treated by BT (intravenous thrombolysis with alteplase prior to mechanical thrombectomy) from three comprehensive stroke centers were analyzed. Patients were divided into non-END group and END group according to whether they developed END within 72 hours of symptom onset. Modified Rankin scale (mRS) was used to assess the patient's prognosis at 90 days, and favorable outcomes were defined as mRS≤2. The incidence of END was investigated, and binary logistic regression analysis was used to explore its associated factors.

RESULTS

The incidence of END after BT was 33.67%. The eligible 90 patients included 29 cases in the END group and 61 cases in the non-END group. Multivariate Logistic regression analysis showed that increase of systolic blood pressure (SBP) (OR=1.026, 95%CI:1.001-1.051, p =0.043), higher level of blood glucose at admission (OR=1.389, 95%CI:1.092-1.176, p =0.007) and large artery atherosclerosis (LAA) subtype (OR=8.009, 95%CI:2.357-27.223, p =0.001) were independent risk factors of END. Compared with the non-END group, the END group had significantly lower rates of good outcomes (6.90% versus 65.57%, p =0.001) while higher rates of mortality (44.83% versus 4.92%, p =0.001).

CONCLUSION

It was found that the incidence of END after BT in AIS patients was 33.67%. An increase in SBP, higher glucose levels at admission, and LAA were independent risk factors of END that predicted a poor prognosis.

Trimethylamine N-Oxide and White Matter Hyperintensity Volume Among Patients With Acute Ischemic Stroke

Importance

Although increasing evidence suggests that trimethylamine N-oxide (TMAO) is associated with atherosclerosis, little is known about whether TMAO and its related metabolites (ie, choline, betaine, and carnitine) are associated with small vessel disease.

Objective

To evaluate the association between TMAO and its related metabolites with features of cerebral small vessel disease, including white matter hyperintensity volume (WMHV) and acute lacunar infarction.

Design, Setting, and Participants

This cross-sectional study included patients enrolled in the Specialized Programs of Translational Research in Acute Stroke biorepository. The registry included 522 patients with acute ischemic stroke who were 18 years or older who presented at the Massachusetts General Hospital or Brigham and Women's Hospital within 9 hours after onset between January 2007 and April 2010. The analyses in this study were conducted between November 2022 and April 2023.

Exposures

Plasma TMAO, choline, betaine, and carnitine were measured by liquid chromatography-tandem mass spectrometry.

Main Outcomes and Measures

WMHV was quantified by a semiautomated approach using signal intensity threshold with subsequent manual editing. Ischemic stroke subtype was classified using the Causative Classification System.

Results

Among 351 patients included in this study, the mean (SD) age was 69 (15) years; 209 patients (59.5%) were male and had a median (IQR) admission National Institute of Health Stroke Scale of 6 (3-13). The magnetic resonance imaging subgroup consisted of 291 patients with a mean (SD) age of 67 (15) years. Among these, the median (IQR) WMHV was 3.2 (1.31-8.4) cm3. TMAO was associated with WMHV after adjustment for age and sex (β, 0.15; 95% CI, 0.01-0.29; P < .001). TMAO remained significant in a multivariate analysis adjusted for age, sex, hypertension, diabetes, and smoking (β, 0.14; 95% CI, 0-0.29; P = .05). TMAO was associated with lacunar stroke but not other ischemic stroke subtypes in a model adjusted for age, sex, hypertension, diabetes, and smoking (OR, 1.67; 95% CI, 1.05-2.66; P = .03).

Conclusions and Relevance

In this observational study, TMAO was associated with cerebral small vessel disease determined by WMHV and acute lacunar infarction. The association was independent of traditional vascular risk factors.

Radiomics Analysis of Diffusion-Weighted Imaging and Long-Term Unfavorable Outcomes Risk for Acute Stroke

BACKGROUND

Diffusion-weighted imaging radiomics could be used as prognostic biomarkers in acute ischemic stroke. We aimed to identify a clinical and diffusion-weighted imaging radiomics model for individual unfavorable outcomes risk assessment in acute ischemic stroke.

METHODS

A total of 1716 patients with acute ischemic stroke from 2 centers were divided into a training cohort and a validation cohort. Patient outcomes were measured with the modified Rankin Scale score. An unfavorable outcome was defined as a modified Rankin Scale score greater than 2. The primary end point was all-cause mortality or outcomes 1 year after stroke. The MRI-DRAGON score was calculated based on previous publications. We extracted and selected the infarct features on diffusion-weighted imaging to construct a radiomic signature. The clinic-radiomics signature was built by measuring the Cox proportional risk regression score (CrrScore) and compared with the MRI-DRAGON score and the ClinicScore. CrrScore model performance was estimated by 1-year unfavorable outcomes prediction.

RESULTS

A high radiomic signature predicted a higher probability of unfavorable outcomes than a low radiomic signature in the training (hazard ratio, 3.19 [95% CI, 2.51-4.05]; P<0.0001) and validation (hazard ratio, 3.25 [95% CI, 2.20-4.80]; P<0.0001) cohorts. The diffusion-weighted imaging Alberta Stroke Program Early CT Score, age, glucose level before therapy, National Institutes of Health Stroke Scale score on admission, glycated hemoglobin' radiomic signature, hemorrhagic infarction, and malignant cerebral edema were associated with an unfavorable outcomes risk after multivariable adjustment. A CrrScore nomogram was developed to predict outcomes and had the best performance in the training (area under the curve, 0.862) and validation cohorts (area under the curve, 0.858). The CrrScore model time-dependent areas under the curve of the probability of unfavorable outcomes at 1 year in the training and validation cohorts were 0.811 and 0.801, respectively.

CONCLUSIONS

The CrrScore model allows the accurate prediction of patients with acute ischemic stroke outcomes and can potentially guide rehabilitation therapies for patients with different risks of unfavorable outcomes.

Predictors of intracranial hemorrhage after mechanical thrombectomy using a stent-retriever for anterior circulation ischemic stroke: A retrospective study

Intracranial hemorrhage (ICH) after mechanical thrombectomy (MT) is a potentially catastrophic complication. We aimed to identify predictors of hemorrhagic complications following MT using a stent-retriever (SR) for acute ischemic stroke (AIS) patients due to large vessel occlusion of anterior circulation. In consecutive AIS patients, the clinical and procedural variables were retrospectively analyzed. ICH was evaluated on computed tomography performed 24 hours following MT and dichotomized into asymptomatic ICH and symptomatic intracranial hemorrhage (SICH) depending on the presence of neurological deterioration. Using univariate and multivariate analyses, the predictors of ICH and SICH were identified. The optimal cutoff value for predicting SICH was determined by receiver operating characteristic (ROC) analysis. Among 135 patients, ICH was detected in 52 (38.5%), and 17 (12.6%) were classified as having SICH. We found that serum glucose level (odds ratio [OR] 1.016, P = .011) and number of SR passes (OR 2.607, P < .001) were significantly correlated with ICH. Independent predictors of SICH included the baseline Alberta stroke program early computed tomography score (ASPECTS) (OR 0.485, P = .042), time from stroke onset to groin puncture (OTP) (OR 1.033, P = .016), and number of SR passes (OR 2.342, P = .038). In ROC analysis, baseline ASPECTS ≤ 7, OTP > 280 minutes, and SR passes > 3 were the optimal cutoff values for predicting SICH. In conclusion, serum glucose level and SR pass serve as predictors for any form of ICH in large vessel occlusion-induced AIS patients undergoing MT. Moreover, patients with lower ASPECTS, prolonged OTP, and multiple SR passes are more vulnerable to SICH.

Effects of Hyperferritinemia on Functional Outcome in Acute Ischemic Stroke Patients with Admission Hyperglycemia

INTRODUCTION

Hyperferritinemia, presented as elevated serum ferritin level, is an indicator of high iron status which plays roles in secondary brain injury after acute ischemic stroke (AIS). However, the effects of hyperferritinemia and poor outcomes remain uncertain. Additionally, admission hyperglycemia quite frequently accompanies AIS patients, which is associated with unfavorable outcome. Thus, we aimed to investigate the effects of hyperferritinemia on 3-month and 1-year functional outcomes in AIS patients and especially those with admission hyperglycemia.

METHODS

AIS patients within 24 h of onset were enrolled at West China Hospital from October 2016 to December 2019. Serum ferritin and blood glucose levels were tested on admission. Poor functional outcome at 3 months and 1 year was defined as modified Rankin Scale score ≥3. Multivariable analysis was used to investigate the associations between hyperferritinemia and 3-month and 1-year outcomes. Subgroup analysis was performed in patients with and without hyperglycemia.

RESULTS

Of 723 patients (mean age 68.11 years, 60.6% males) finally included, 347 (48.0%) had hyperferritinemia. The incidence of poor outcome was 45.2% at 3 months and 41.2% at 1 year. Patients with hyperferritinemia had a higher frequency of poor 3-month outcome (51.8% vs. 39.2%, p = 0.001) and poor 1-year outcome (46.8% vs. 36.1%, p = 0.004). In all AIS patients, hyperferritinemia was not independently associated with poor functional outcome at 3 months or 1 year after adjusting for confounders (all p > 0.05). In AIS patients with hyperglycemia, hyperferritinemia was an independent factor correlated with poor 3-month outcome (OR = 1.711, 95% CI 1.093-2.681, p = 0.019) but not with poor 1-year outcome (p > 0.05).

CONCLUSIONS

High iron status, presented as hyperferritinemia, is associated with poor 3-month functional outcome in AIS patients with hyperglycemia. Evaluating serum ferritin level may be conducive to assess the risk of short-term poor outcome in AIS patients with hyperglycemia. Further studies will be required to confirm our findings.

The acute-to-chronic glycemic ratio correlates with the severity of illness at admission in patients with diabetes experiencing acute ischemic stroke

Acute hyperglycemia is a powerful indicator of the severity of acute ischemic stroke (AIS); however, the relationship between these two factors is not very clear in patients with diabetes. We aimed to retrospectively evaluate data from 335 consecutive patients who experienced AIS from November 2015 to November 2016 to investigate whether a comprehensive assessment of blood glucose levels is a more valuable indicator of the severity of AIS or the presence of acute hyperglycemia in patients with diabetes. We collected demographic data, clinical manifestation information, clinical scores, and laboratory data [including fasting blood glucose and glycated hemoglobin (HbA1c) levels]. We estimated prehospital mean blood glucose concentrations using the following formula [1.59 * HbA1c (%) – 2.59] to calculate the “Acute-to-Chronic Glycemic Ratio” (AC ratio). The AC ratio differed significantly among patients grouped according to the National Institutes of Health Stroke Scale/Score (NIHSS) at admission (admission NIHSS) (p = 0.006). Univariate regression analysis revealed a correlation between the AC ratio and admission NIHSS [standardized β-coefficient (Std. B) = 0.164, p = 0.004]. The adjusted linear regression analysis revealed a correlation between both HbA1c (Std. B = 0.368, p = 0.038) and the AC ratio (Std. B = 0.262, p = 0.022) and admission NIHSS. The AC ratio (Std. B = 0.161, p = 0.012) was related to admission NIHSS in the stepwise variable selection. For an admission NIHHS &gt; 4, the AC ratio (Std. B = 0.186, p = 0.047) was related to admission NIHSS in the stepwise variable selection. The AC ratio (Std. B = 1.163, p = 0.006 and Std. B = 0.565, p = 0.021, respectively) were related to admission NIHSS in both large-artery atherosclerosis (LAA) and small-vessel occlusion (SVO) subgroups. Thus, the AC ratio is related to admission NIHSS in patients with diabetes who experienced AIS and may be a better indicator of severity than acute blood glucose levels.

Analysis of influencing factors of early neurological improvement after intravenous rt-PA thrombolysis in acute anterior circulation ischemic stroke

Background and objective

It has been widely reported that Early neurological improvement (ENI) after rt-PA intravenous thrombolysis contributes to a good long-term prognosis in patients experiencing acute ischemic stroke (AIS). However, which clinical factors influence after intravenous administration of recombinant tissue-type plasminogen activator (IV-rt PA) in AIS patients ENI is still unclear. This study aimed to evaluate the impact of influencing factors on the benefit of ENI after intravenous thrombolysis neurological improvement after IV-rt PA.

Methods

The data of 73 patients with acute anterior circulation ischemic stroke who received intravenous thrombolysis with rt-PA in Chongqing University Jiangjin Hospital from January 2021 to July 2022 were retrospectively studied. According to the change rate of 24 h NISHH score, the research subjects were divided into the recovery group, the significant curative effect group, the curative effect group and the no curative effect group, the ENI after intravenous thrombolysis with rt-PA was defined as the improvement rate of National Institutes of Health Stroke Scale (NIHSS)score >46% at 24 h after IV-rt PA, and univariate factor analysis was used Clinical factors associated with ENI after intravenous thrombolysis.

Results

According to the 24-h NIHSS improvement rate of rt-PA intravenous thrombolysis in patients with acute anterior circulation ischemic stroke, 35 cases (47.95%) of the study population had ENI. There was no statistical difference between the improvement and non-improvement group in general demographic data, stroke TOAST classification, stroke risk factors (history of stroke, heart disease, hyperlipidemia, hypertension), and laboratory test data. There was a statistically significant difference in the random blood glucose levels between the two groups (p < 0.001, t = 3.511).

Conclusion

The effect of rt-PA intravenous thrombolysis within the time window of patients with acute anterior circulation ischemic stroke is significant, but the ENI after thrombolysis is easily affected by the level of blood glucose; diabetes is the most important factor affecting the acute anterior circulation ischemic stroke patients Clinical factors of ENI after intravenous thrombolysis with rt-PA.

Hyperglycemia in acute ischemic stroke: physiopathological and therapeutic complexity

Diabetes mellitus and associated chronic hyperglycemia enhance the risk of acute ischemic stroke and lead to worsened clinical outcome and increased mortality. However, post-stroke hyperglycemia is also present in a number of non-diabetic patients after acute ischemic stroke, presumably as a stress response. The aim of this review is to summarize the main effects of hyperglycemia when associated to ischemic injury in acute stroke patients, highlighting the clinical and neurological outcomes in these conditions and after the administration of the currently approved pharmacological treatment, i.e. insulin. The disappointing results of the clinical trials on insulin (including the hypoglycemic events) demand a change of strategy based on more focused therapies. Starting from the comprehensive evaluation of the physiopathological alterations occurring in the ischemic brain during hyperglycemic conditions, the effects of various classes of glucose-lowering drugs are reviewed, such as glucose-like peptide-1 receptor agonists, DPP-4 inhibitors and sodium glucose cotransporter 2 inhibitors, in the perspective of overcoming the up-to-date limitations and of evaluating the effectiveness of new potential therapeutic strategies.

Comparative Studies of Cerebral Reperfusion Injury in the Posterior and Anterior Circulations After Mechanical Thrombectomy

Cerebral reperfusion injury is the major complication of mechanical thrombectomy (MT) for acute ischemic stroke (AIS). Contrast extravasation (CE) and intracranial hemorrhage (ICH) are the key radiographical features of cerebral reperfusion injury. The aim of this study was to investigate CE and ICH after MT in the anterior and posterior circulation, and their effect on functional outcome. This is a retrospective study of all consecutive patients who were treated with MT for AIS at University of California Irvine Medical Center between January 1, 2014, and December 31, 2017. Patient characteristics, clinical features, procedural variables, contrast extravasation, ICH, and outcomes after MT were analyzed. A total of 131 patients with anterior circulation (AC) stroke and 25 patients with posterior circulation (PC) stroke underwent MT during the study period. There was no statistically significant difference in admission NIHSS score, blood pressure, rate of receiving intravenous tPA, procedural variables, contrast extravasation, and symptomatic ICH between the 2 groups. Patients with PC stroke had a similar rate of favorable outcome (mRS 0–2) but significantly higher mortality (40.0% vs. 10.7%, p < 0.01) than patients with AC stroke. Multivariate regression analysis identified initial NIHSS score (OR 1.1, CI 1.0–1.2, p = 0.01), number of passes with stent retriever (OR 2.1, CI 1.3–3.6, p < 0.01), and PC stroke (OR 9.3, CI 2.5–35.1, p < 0.01) as independent risk factors for death. There was no significant difference in functional outcomes between patients with and without evidence of cerebral reperfusion injury after MT. We demonstrated that AC and PC stroke had similar rates of cerebral reperfusion injury and favorable outcome after MT. Cerebral reperfusion injury is not a significant independent risk factor for poor functional outcome.

Visualizing Oxidative Stress Level for Timely Assessment of Ischemic Stroke via a Ratiometric Near-Infrared-II Luminescent Nanoprobe

Ischemic stroke (IS) characterized with high morbidity and mortality rates is considered as one of the most dangerous brain diseases. The timely assessment of IS is crucial for making a clinical decision due to the severity of IS featured with time-dependence. Herein, we develop a highly reactive oxygen species (HROS)-responsive ratiometric near-infrared-II (NIR-II) nanoprobe based on a dye-sensitized system between IR-783 dye and lanthanide-doped nanoparticles. Once intravenously injected into the mice, the probe is rapidly accumulated at a lesion site by recognizing the activated endothelial cell or impaired blood-brain barrier (BBB) in the ischemic area and further responds to HROS, thereby allowing in vivo imaging of the oxidative stress level. The probe is not only able to discriminate the salvageable ischemic tissue from infarcted stroke core by visualizing the enriched degree of the probe at the lesion site but also can grade the salvageable ischemic tissue by analyzing the oxidative stress level. In addition, the ischemia area was clearly delineated by NIR-II luminescence imaging after cerebral ischemia for 30 min, which is significantly earlier than with the magnetic resonance imaging (MRI) method, thereby providing a practical tool for the timely assessing of IS.

Uric Acid and Gluconic Acid as Predictors of Hyperglycemia and Cytotoxic Injury after Stroke

Hyperglycemia is a feature of worse brain injury after acute ischemic stroke, but the underlying metabolic changes and the link to cytotoxic brain injury are not fully understood. In this observational study, we applied regression and machine learning classification analyses to identify metabolites associated with hyperglycemia and a neuroimaging proxy for cytotoxic brain injury. Metabolomics and lipidomics were carried out using liquid chromatography-tandem mass spectrometry in admission plasma samples from 381 patients presenting with an acute stroke. Glucose was measured by a central clinical laboratory, and a subgroup of patients (n = 201) had apparent diffusion coefficient (ADC) imaging quantified on magnetic resonance imaging (MRI) to estimate cytotoxic injury. Uric acid was the leading metabolite in univariate analysis of both hyperglycemia (OR 19.6, 95% CI 8.6-44.7, P = 1.44 × 10-12) and ADC (OR 5.3, 95% CI 2.2-13.0, P = 2.42 × 10-4). To further prioritize model features and account for non-linear correlation structure, a random forest machine learning algorithm was applied to separately model hyperglycemia and ADC. The statistical techniques used have identified uric acid and gluconic acids as leading candidate markers common to all models (R2 = 68%, P = 2.2 × 10-10 for uric acid; R2 = 15%, P = 8.09 × 10-10 for gluconic acid). Both uric acid and gluconic acid were associated with hyperglycemia and cytotoxic brain injury. Both metabolites are linked to oxidative stress, which highlights two candidate targets for limiting brain injury after stroke.

Mens Sana in Corpore Sano: Does the Glycemic Index Have a Role to Play?

Although diet interventions are mostly related to metabolic disorders, nowadays they are used in a wide variety of pathologies. From diabetes and obesity to cardiovascular diseases, to cancer or neurological disorders and stroke, nutritional recommendations are applied to almost all diseases. Among such disorders, metabolic disturbances and brain function and/or diseases have recently been shown to be linked. Indeed, numerous neurological functions are often associated with perturbations of whole-body energy homeostasis. In this regard, specific diets are used in various neurological conditions, such as epilepsy, stroke, or seizure recovery. In addition, Alzheimer’s disease and Autism Spectrum Disorders are also considered to be putatively improved by diet interventions. Glycemic index diets are a novel developed indicator expected to anticipate the changes in blood glucose induced by specific foods and how they can affect various physiological functions. Several results have provided indications of the efficiency of low-glycemic index diets in weight management and insulin sensitivity, but also cognitive function, epilepsy treatment, stroke, and neurodegenerative diseases. Overall, studies involving the glycemic index can provide new insights into the relationship between energy homeostasis regulation and brain function or related disorders. Therefore, in this review, we will summarize the main evidence on glycemic index involvement in brain mechanisms of energy homeostasis regulation.

Effect of Huoxiang Zhengqi Pill on Early Neurological Deterioration in Patients with Acute Ischemic Stroke Undergoing Recanalization Therapy and Predictive Effect of Essen Score

Early neurologic deterioration (END) in the acute phase of ischemic stroke is a serious clinical event, which is closely related to poor prognosis. Therefore, it is important to identify presentation features that predict END and take relevant treatment measures, as they could help to prevent the deterioration of high-risk patients. The prospective intervention study was carried out from January 2018 to December 2019. We included consecutive patients hospitalized for acute ischemic stroke (AIS) within 6 hours of onset. Patients were randomly assigned (1 : 1) to recanalization therapy plus Huoxiang Zhengqi Pill (HXZQ) (intervention group) or standard recanalization therapy alone (control group). The primary outcome was the development of END according to predefined criteria within the first 1 week of stroke onset. Poisson regression was used to identify predictors for END. Of the 155 patients enrolled in the study (age, 63 ± 11 years; 28.4% female), 20 (12.9%) developed END. Univariate analysis showed that the use of HXZQ and Essen stroke risk score (ESRS) (low risk group) were protective factors for END, while advanced age was a risk factor for END. However, in multivariate analysis, only ESRS (OR, 0.232; 95%CI, 0.058–0.928; P=0.039) and the use of HXZQ (OR, 0.297; 95%CI, 0.096–0.917; P=0.035) were statistically significant. ESRS can be used as the prediction factor of END. HXZQ has small side effects and wide indication. It could be used in the treatment of AIS.

Elevated glucose is associated with hemorrhagic transformation after mechanical thrombectomy in acute ischemic stroke patients with severe pretreatment hypoperfusion

Several pretreatment variables such as elevated glucose and hypoperfusion severity are related to brain hemorrhage after endovascular treatment of acute stroke. We evaluated whether elevated glucose and severe hypoperfusion have synergistic effects in the promotion of parenchymal hemorrhage (PH) after mechanical thrombectomy (MT). We included 258 patients MT-treated who had a pretreatment computed tomography perfusion (CTP) and a post-treatment follow-up MRI. Severe hypoperfusion was defined as regions with cerebral blood volume (CBV) values < 2.5% of normal brain [very-low CBV (VLCBV)-regions]. Median baseline glucose levels were 119 (IQR = 105-141) mg/dL. Thirty-nine (15%) patients had pretreatment VLCBV-regions, and 42 (16%) developed a PH after MT. In adjusted models, pretreatment glucose levels interacted significantly with VLCBV on the prediction of PH (p-interaction = 0.011). In patients with VLCBV-regions, higher glucose was significantly associated with PH (adjusted-OR = 3.15; 95% CI = 1.08-9.19, p = 0.036), whereas this association was not significant in patients without VLCBV-regions. CBV values measured at pretreatment CTP in coregistered regions that developed PH or infarct at follow-up were not correlated with pretreatment glucose levels, thus suggesting the existence of alternative deleterious mechanisms other than direct glucose-driven hemodynamic impairments. Overall, these results suggest that both severe hypoperfusion and glucose levels should be considered in the evaluation of adjunctive neuroprotective strategies.

Empagliflozin attenuates transient cerebral ischemia/reperfusion injury in hyperglycemic rats via repressing oxidative-inflammatory-apoptotic pathway

Hyperglycemia is one of the ischemic neuronal damage triggers that exacerbate the response to oxidative stress, inflammation, and apoptosis induced by cerebral ischemia/reperfusion (I/R) injury. Empagliflozin, a sodium-glucose cotransporter 2 (SGLT 2) inhibitor, was shown to effectively reduce hyperglycemia and glucotoxicity besides improving glycemic control in diabetics. Therefore, the present study was conducted to investigate the neuroprotective effect of empagliflozin against cerebral I/R injury in hyperglycemic rats. Hyperglycemia was induced by streptozotocin (55 mg/kg), and transient cerebral I/R was induced by bilateral common carotid occlusion for 30 min followed by 24-h reperfusion. Either empagliflozin (10 mg/kg; i.p.) or gliclazide (2 mg/kg, p.o.) was administered at 1 and 24 h after reperfusion. Treatment with empagliflozin showed a significant amelioration of behavioral/neurological functions and histopathological changes observed in brain tissues of hyperglycemic rats subjected to cerebral I/R injury. Comparable to gliclazide, empagliflozin decreased cerebral infarct volume along with suppression of cerebral oxidative stress, inflammatory, and apoptotic markers in brain tissues of hyperglycemic I/R-injured rats. These findings suggested that empagliflozin can significantly alleviate neuronal damage resulting from global I/R injury induced in hyperglycemic rats. The proposed neuroprotective effect of empagliflozin may be attributed to its glycemic control effect and related antioxidant, anti-inflammatory, and antiapoptotic effects.

MFG-E8 alleviates oxygen-glucose deprivation-induced neuronal cell apoptosis by STAT3 regulating the selective polarization of microglia

Background: Ischemic stroke is a complex pathological process, involving inflammatory reaction, energy metabolism disorder, free radical injury, cell apoptosis and other aspects. Accumulating evidences have revealed that MFG-E8 had a protective effect on multiple organ injuries. However, the comprehensive function and mechanism of MFG-E8 in ischemic brain remain largely unclear.Methods: BV-2 cells were treated with recombinant murine MFG-E8 (rmMFG-E8) or/and Colivelin TFA after exposing for 4 h with oxygen glucose deprivation (OGD). Cell viability and apoptosis were assessed by MTT assay and Flow cytometry. RT-qPCR and Western blot assays were applied to examine the expression levels of MFG-E8, apoptosis-related proteins and M1/M2 polarization markers.Results: Our results demonstrated that OGD significantly inhibited microglial viability and facilitated apoptosis. In addition, we found that OGD downregulated MFG-E8 expression, and MFG-E8 inhibited OGD-induced microglial apoptosis and promoted microglial M2 polarization. In terms of mechanism, we proved that MFG-E8 regulated OGD-induced microglial M1/M2 polarization by inhibiting p-STAT3 and SOCS3 expressions, which was reversed by STAT3 activator (Colivelin TFA). Finally, we verified MFG-E8 alleviated OGD-induced neuronal cell apoptosis by M2 polarization of BV-2 cells.Conclusions: We demonstrated that MFG-E8 reduced neuronal cell apoptosis by enhancing activation of microglia via STAT3 signaling. Therefore, we suggested that MFG-E8 might provide a novel mechanism for ischemic stroke.

Preconditioning with partial caloric restriction confers long-term protection against grey and white matter injury after transient focal ischemia

Caloric restriction (CR) has been extensively examined as a preventative strategy against aging and various diseases, but CR effects on cerebral ischemia are largely unknown. We subjected C57BL6/J mice to ad libitum food access (LF) or a diet restricted to 70% of ad libitum food access (RF) for two to four weeks followed by 60 min of transient focal ischemia (tFCI). RF for four weeks protected against subsequent tFCI-induced infarct. RF improved sensorimotor function after stroke in the foot fault and corner tests, as well as performance in the Morris water maze test. In addition, RF preserved ischemic white matter tract integrity assessed by histology and compound action potential. Sirt1 and Sirt3 were both upregulated in RF ischemic brain, but heterozygous deletion of Sirt1 or knockout of Sirt3 did not alter the protection induced by RF against ischemic injury. RF induced significant release of adiponectin, a hormone related to glucose metabolism. Knockout of adiponectin decreased RF-induced protection after tFCI. These data demonstrate the novel finding that white matter, as well as neurons, benefit from CR prior to cerebral ischemic injury, and that adiponectin may contribute to these protective effects.

Microembolic Signals is Associated With Insulin Resistance Among Acute Ischemic Stroke Patients

BACKGROUND

Microembolic signals (MES) and insulin resistance (IR) is common in patients with acute ischemic stroke (AIS). Patients with active MES tend to be more seriously ill and prone to aggravating disease progression. IR is an important risk factor for stroke which has been found to be associated with the severity of stroke. This study aims to investigate the clinical correlation between intracranial MES and IR in AIS patients.

METHODS

A total of 119 patients with AIS were enrolled in this study. The IR index (HOMA-IR) was calculated according to the homeostasis model and divided into 4 levels, where IR was defined by HOMA-IR index in the top quartile (Q4). Transcranial Doppler Sonography was performed in all patients within 72 hours after the stroke onset to monitor arterial MES in the lesion side of the brain for 30 minutes.

RESULTS

It is found that the positive rate of MES increased with the increase of IR level. The positive rate of MES in IR group was 55.2% (16/29), and that in non-IR group was 32.2% (29/90). In addition, HOMA-IR in patients with MES- were significantly lower than those in patients with MES+ (1.6 [Interquartile range: 0.9-2.5] compared with 2.2 [Interquartile range: 1.3-4.1], P < .05).In multiple logistic regression analysis, we calculated the OR of MES as compared with the HOMA-IR. The result of OR value is 1.38 (95% confidence interval: 1.05-1.82, P = .02).

CONCLUSIONS

IR is positively related to MES in patients with AIS. Higher level of IR might contribute to plaque destabilization and the formation of MES, which finally leading to the occurrence of stroke.

A new era for stroke therapy: Integrating neurovascular protection with optimal reperfusion

Recent advances in stroke reperfusion therapies have led to remarkable improvement in clinical outcomes, but many patients remain severely disabled, due in part to the lack of effective neuroprotective strategies. In this review, we show that 95% of published preclinical studies on "neuroprotectants" (1990-2018) reported positive outcomes in animal models of ischemic stroke, while none translated to successful Phase III trials. There are many complex reasons for this failure in translational research, including that the majority of clinical trials did not test early delivery of neuroprotectants in combination with successful reperfusion. In contrast to the clinical trials, >80% of recent preclinical studies examined the neuroprotectant in animal models of transient ischemia with complete reperfusion. Furthermore, only a small fraction of preclinical studies included long-term functional assessments, aged animals of both genders, and models with stroke comorbidities. Recent clinical trials demonstrate that 70%-80% of patients treated with endovascular thrombectomy achieve successful reperfusion. These successes revive the opportunity to retest previously failed approaches, including cocktail drugs that target multiple injury phases and different cell types. It is our hope that neurovascular protectants can be retested in future stroke research studies with specific criteria outlined in this review to increase translational successes.

Association between Increased Matrix Metalloproteinase-9 (MMP-9) Levels with Hyperglycaemia Incidence in Acute Ischemic Stroke Patients

BACKGROUND:

Hyperglycemia is common in acute stroke patients. Hyperglycemia can induce the production of reactive oxygen species, causing increased activity of matrix metalloproteinase-9 (MMP-9).

AIM:

This study aimed to determine an association between the increased levels of MMP-9 and the incidence of hyperglycemia in acute ischemic stroke patients.

METHODS:

This is a case-control study. Acute ischemic stroke patients admitted to the Stroke Unit of a reference hospital in Yogyakarta, Indonesia was divided into the hyperglycemic and non-hyperglycemic group. Demographic and clinical characteristics of each subject were recorded, and blood levels of MMP-9 were measured. Seventy-one patients were recruited, 40 subjects in the hyperglycemic group and 31 subjects in the non-hyperglycemic group.

RESULTS:

The median levels of blood MMP-9 level in the hyperglycemic and non-hyperglycemic group were 974.37 and 748.48 ng/mL, respectively, and the difference was statistically not significant (95% CI, 191.24-2849.53; p = 0.07). When the calculated cut-off point of 600.99 ng/mL was used, the proportion of patients with higher MMP-9 levels was significantly more in the hyperglycemic group compared with the ones in the non-hyperglycemic group (82.5% and 54.8%, respectively; OR = 3.88; p = 0.011).

CONCLUSION:

We concluded that the proportion of patients with MMP-9 level >600.99 ng/mL was significantly higher in acute ischemic stroke patients with hyperglycemia.

Hyperglycaemia does not increase perfusion deficits after focal cerebral ischaemia in male Wistar rats

Background:

Hyperglycaemia is associated with a worse outcome in acute ischaemic stroke patients; yet the pathophysiological mechanisms of hyperglycaemia-induced damage are poorly understood. We hypothesised that hyperglycaemia at the time of stroke onset exacerbates ischaemic brain damage by increasing the severity of the blood flow deficit.

Methods:

Adult, male Wistar rats were randomly assigned to receive vehicle or glucose solutions prior to permanent middle cerebral artery occlusion. Cerebral blood flow was assessed semi-quantitatively either 1 h after middle cerebral artery occlusion using ^99mTc-D, L-hexamethylpropyleneamine oxime (^99mTc-HMPAO) autoradiography or, in a separate study, using quantitative pseudo-continuous arterial spin labelling for 4 h after middle cerebral artery occlusion. Diffusion weighted imaging was performed alongside pseudo-continuous arterial spin labelling and acute lesion volumes calculated from apparent diffusion coefficient maps. Infarct volume was measured at 24 h using rapid acquisition with refocused echoes T₂-weighted magnetic resonance imaging.

Results:

Glucose administration had no effect on the severity of ischaemia when assessed by either ^99mTc-HMPAO autoradiography or pseudo-continuous arterial spin labelling perfusion imaging. In comparison to the vehicle group, apparent diffusion coefficient–derived lesion volume 2–4 h post-middle cerebral artery occlusion and infarct volume 24 h post-middle cerebral artery occlusion were significantly greater in the glucose group.

Conclusions:

Hyperglycaemia increased acute lesion and infarct volumes but there was no evidence that the acute blood flow deficit was exacerbated. The data reinforce the conclusion that the detrimental effects of hyperglycaemia are rapid, and that treatment of post-stroke hyperglycaemia in the acute period is essential but the mechanisms of hyperglycaemia-induced harm remain unclear.

Apparent Diffusion Coefficient Signal Intensity Ratio Predicts the Effect of Revascularization on Ischemic Cerebral Edema

BACKGROUND

Apparent diffusion coefficient (ADC) imaging is a biomarker of cytotoxic injury that predicts edema formation and outcome after ischemic stroke. It therefore has the potential to serve as a "tissue clock" to describe the extent of ischemic injury and potentially predict response to therapy. The goal of this study was to determine the relationship between baseline ADC signal intensity, revascularization, and edema formation.

METHODS

We examined the ADC signal intensity ratio (ADCr) of the stroke lesion (defined as the baseline DWI hyperintense region) compared to the contralateral normal hemisphere in 65 subjects from the Mechanical Retrieval and Recanalization of Stroke Clots Using Embolectomy trial. The associations between ADCr, neurologic outcome, and cerebral edema were examined. Finally, we explored the interaction between baseline ADCr and vessel recanalization at day 7 on post-stroke edema.

RESULTS

We found that lower initial ADCr was associated with a worse outcome on the modified Rankin Scale (mRS) at 90 days (52.2% of those with ADCr <64% were mRS 5-6 vs. 19.1% with ADCr ≥64%, p = 0.006). Those subjects with reconstitution of flow distal to the initial vessel occlusion showed greater normalization of ADCr on follow-up scan (increase in ADCr of 16.4 ± 2.07 vs. 1.99 ± 4.33%, p = 0.0039). In those patients with low baseline ADCr, successful revascularization was associated with reduced edema (median swelling volume 164 mL [interquartile range (IQR) 53.3-190 mL] vs. 20.7 mL [IQR 3.20-55.1 mL], p = 0.024).

CONCLUSIONS

This study reaffirms the association of ADCr with outcome after stroke, supports the idea that reperfusion may attenuate rather than enhance post-stroke edema, and indicates that the degree of edema with and without revascularization may be predicted by ADCr.

High Dietary Glycemic Load is Associated with Poor Functional Outcome in Patients with Acute Cerebral Infarction

Background and Purpose

Elevated postprandial blood glucose is a critical risk factor for stroke. The dietary glycemic load (GL) and glycemic index (GI) are frequently used as markers of the postprandial blood glucose response to estimate the overall glycemic effect of diets. We hypothesized that high dietary GL, GI, or total carbohydrate intake is associated with a poor functional outcome in patients with acute ischemic stroke.

Methods

We prospectively included 263 first-ever ischemic stroke patients who completed a semiquantitative food-frequency questionnaire. The dietary GL, GI, and total carbohydrate intake were investigated by examining the average frequency of intake during the previous year based on reference amounts for various food items. Poor functional outcome was defined as a score on the modified Rankin Scale (mRS) of ≥3 at 3 months after stroke.

Results

The patients were aged 65.4±11.7 years (mean±standard deviation), and 58.2% of them were male. A multivariate analysis adjusted for age, sex, marital status, prestroke mRS score, diabetes mellitus, hyperlipidemia, body mass index, triglycerides, low-density lipoprotein, hemoglobin A1c, stroke classification, and National Institutes of Health Stroke Scale score, early neurological deterioration, and high-grade white-matter hyperintensities revealed that the dietary GL and total carbohydrate intake were associated with a poor functional outcome, with odds ratios for the top quartile relative to the bottom quartile of 28.93 (95% confidence interval=2.82–296.04) and 36.84 (95% confidence interval=2.99–453.42), respectively (p for trend=0.002 and 0.002, respectively). In contrast, high dietary GI was not associated with a poor functional outcome (p for trend=0.481).

Conclusions

Increased dietary GL and carbohydrate intake were associated with a poor short-term functional outcome after an acute ischemic stroke.

Peroxisome proliferator-activated receptor γ (PPARγ): A master gatekeeper in CNS injury and repair

Peroxisome proliferator-activated receptor γ (PPARγ) is a widely expressed ligand-modulated transcription factor that governs the expression of genes involved in inflammation, redox equilibrium, trophic factor production, insulin sensitivity, and the metabolism of lipids and glucose. Synthetic PPARγ agonists (e.g. thiazolidinediones) are used to treat Type II diabetes and have the potential to limit the risk of developing brain injuries such as stroke by mitigating the influence of comorbidities. If brain injury develops, PPARγ serves as a master gatekeeper of cytoprotective stress responses, improving the chances of cellular survival and recovery of homeostatic equilibrium. In the acute injury phase, PPARγ directly restricts tissue damage by inhibiting the NFκB pathway to mitigate inflammation and stimulating the Nrf2/ARE axis to neutralize oxidative stress. During the chronic phase of acute brain injuries, PPARγ activation in injured cells culminates in the repair of gray and white matter, preservation of the blood-brain barrier, reconstruction of the neurovascular unit, resolution of inflammation, and long-term functional recovery. Thus, PPARγ lies at the apex of cell fate decisions and exerts profound effects on the chronic progression of acute injury conditions. Here, we review the therapeutic potential of PPARγ in stroke and brain trauma and highlight the novel role of PPARγ in long-term tissue repair. We describe its structure and function and identify the genes that it targets. PPARγ regulation of inflammation, metabolism, cell fate (proliferation/differentiation/maturation/survival), and many other processes also has relevance to other neurological diseases. Therefore, PPARγ is an attractive target for therapies against a number of progressive neurological disorders.

Insulin resistance in ischemic stroke

Insulin resistance often refers to a pathological condition in which cells fail to respond to the normal actions of insulin. Increasing literature has noted a critical role of insulin resistance in the pathogenesis of ischemic stroke. Insulin resistance plays an important role in the pathogenesis of ischemic stroke via enhancing advanced changes of atherosclerosis. A variety of literature indicates that insulin resistance enhances platelet adhesion, activation and aggregation which are conducive to the occurrence of ischemic stroke. Insulin resistance also induces hemodynamic disturbances and contributes to the onset of ischemic stroke. In addition, insulin resistance may augment the role of the modifiable risk factors in ischemic stroke and induce the occurrence of ischemic stroke. Preclinical and clinical studies have supported that improving insulin resistance may be an effective measure to prevent or delay ischemic stroke.

Critical Care Management of Acute Ischemic Stroke

OPINION STATEMENT

Ischemic stroke accounts for approximately 85% of all strokes. Although severe strokes constitute a minority of cases, they are associated with a majority of the subsequent disability and death. Reperfusion therapy with intravenous tissue plasminogen activator (tPA) and/or endovascular thrombectomy is a mainstay of acute stroke management. Intensive care management of stroke is focused on reducing complications of reperfusion, such as hemorrhagic transformation, and minimizing secondary brain injury, including brain edema and progressive stroke. Additionally, severe stroke patients frequently need ventilatory or hemodynamic support provided in an intensive care unit (ICU) setting. Here, we discuss the current medical and surgical ICU management aspects of acute ischemic stroke and identify areas where ongoing studies may reveal new treatments to improve neurological recovery.