Moderate hyperglycemia worsens acute blood-brain barrier injury after forebrain ischemia in rats

Clinically Asymptomatic Hemorrhagic Conversion Is Associated with Need for Inpatient Rehabilitation After Mechanical Thrombectomy for Anterior Circulation Ischemic Stroke

BACKGROUND

Hemorrhagic conversion (HC) is a known complication after acute ischemic stroke (AIS) in patients undergoing mechanical thrombectomy (MT). Although symptomatic HC has been shown to lead to poor neurologic outcomes, the effect of asymptomatic HC (aHC) is unclear. This study aims to identify predictors of aHC and to determine the short-term outcomes.

METHODS

This is a single-institution retrospective study of patients with anterior circulation stroke (AIS) who underwent MT between January 2016 and September 2022. Radiographic HC was identified on postoperative imaging. Asymptomatic hemorrhage was defined as no acute neurologic decline attributable to imaging findings. Baseline characteristics, technical aspects, and outcomes were compared between aHC and no-HC groups. Logistic regression and multivariate analysis were performed.

RESULTS

A total of 615 patients underwent MT for AIS, of whom 496 met the inclusion criteria. A total of 235 patients (47.4%) had evidence of aHC. Diabetes mellitus (odds ratio [OR], 1.59; 95% confidence interval [CI], 1.06-2.41; P = 0.03), hyperglycemia (OR, 1.01; 95% CI, 1.00-1.01; P = 0.002), greater number of passes (OR, 1.14; 95% CI, 1.00-1.31; P = 0.05), and longer time to reperfusion (OR, 1.02; 95% CI, 1.00-1.05; P = 0.05) were associated with aHC. Patients with aHC were significantly more likely to require rehabilitation, whereas those without HC were more likely to be discharged home (P < 0.001). There were no significant differences in long-term outcomes.

CONCLUSIONS

HC occurred in up to half of patients who underwent MT for AIS, most of whom were clinically asymptomatic. Despite clinical stability, aHC was significantly associated with a greater need for inpatient rehabilitation. Predictors of aHC included hyperglycemia and a longer time to reperfusion.

Improving stroke outcomes in hyperglycemic mice by modulating tPA/NMDAR signaling to reduce inflammation and hemorrhages

ABSTRACT

The pharmacological intervention for ischemic stroke hinges on intravenous administration of the recombinant tissue-type plasminogen activator (rtPA, Alteplase/Actilyse) either as a standalone treatment or in conjunction with thrombectomy. However, despite its clinical significance, broader use of rtPA is constrained because of the risk of hemorrhagic transformations (HTs). Furthermore, the presence of diabetes or chronic hyperglycemia is associated with an elevated risk of HT subsequent to thrombolysis. This detrimental impact of tPA on the neurovascular unit in patients with hyperglycemia has been ascribed to its capacity to induce endothelial N-methyl-D-aspartate receptor (NMDAR) signaling, contributing to compromised blood-brain barrier integrity and neuroinflammatory processes. In a mouse model of thromboembolic stroke with chronic hyperglycemia, we assessed the effectiveness of rtPA and N-acetylcysteine (NAC) as thrombolytic agents. We also tested the effect of blocking tPA/NMDAR signaling using a monoclonal antibody, Glunomab. Magnetic resonance imaging, speckle contrast imaging, flow cytometry, and behavioral tasks were used to evaluate stroke outcomes. In hyperglycemic animals, treatment with rtPA resulted in lower recanalization rates and increased HTs. Conversely, NAC treatment reduced lesion sizes while mitigating HTs. After a single administration, either in standalone or combined with rtPA-induced thrombolysis, Glunomab reduced brain lesion volumes, HTs, and neuroinflammation after stroke, translating into improved neurological outcomes. Additionally, we demonstrated the therapeutic efficacy of Glunomab in combination with NAC or as a standalone strategy in chronic hyperglycemic animals. Counteracting tPA-dependent endothelial NMDAR signaling limits ischemic damages induced by both endogenous and exogenous tPA, including HTs and inflammatory processes after ischemic stroke in hyperglycemic animals.

Increased Neuron-Specific Enolase Level Predicts Symptomatic Intracranial Hemorrhage in Patients with Ischemic Stroke Treated with Endovascular Treatment

BACKGROUND

Neuron-specific enolase (NSE), which is a highly specific marker for neurons, could be a predictor for prognosis in patients with symptomatic intracranial hemorrhage (sICH) with acute ischemic stroke who are receiving endovascular treatment (EVT). This study aimed to investigate the relationship between NSE and sICH in patients with acute anterior circulation stroke undergoing EVT.

METHODS

A total of 215 consecutive patients with acute stroke treated with EVT were included. Patients with stroke and acute anterior circulation occlusion, receiving EVT treated at our hospital, were enrolled between January 2017 and August 2021. NSE level was measured on arrival at the neurology intensive care unit after EVT. The patients were divided into 2 groups according to whether sICH was present. Univariate and multivariate analyses were performed. NSE level was also incorporated into the TAG score (modified Thrombolysis in Cerebral Infarction score, Alberta Stroke Program Early CT Score, and glucose level), which was developed as a scoring system to predict sICH, and the prediction capability was compared with the TAG score alone. Causal inference was performed using the package DoWhy in Python to evaluate the causal relationship between NSE and sICH.

RESULTS

The area under the curve (AUC) value of NSE showed moderate accuracy, with an AUC value of 0.729 (95% confidence interval, 0.655-0.795; P < 0.001). The NSE cutoff value was set at 23.88 ng/mL. When the NSE level ≥23.88 ng/mL, the sensitivity was 58.33% and the specificity was 78.72% (P < 0.001). The AUC for the TAG + NSE score was 0.801 compared with an AUC of 0.632 for the TAG score (Z = 2.034; P = 0.042). A causal inference model using the DoWhy library shows a proportional relationship between NSE and the diagnosis of sICH.

CONCLUSIONS

This study is the first to show that increased NSE level is an independent predictor of sICH in patients with acute anterior circulation stroke who are undergoing endovascular treatment.

Predictors of failure of early neurological improvement in early time window following endovascular thrombectomy: a multi-center study

Background and objective

Endovascular thrombectomy (EVT) has become the gold standard in the treatment of acute stroke patients. However, not all patients respond well to this treatment despite successful attempts. In this study, we aimed to identify variables associated with the failure of improvements following EVT.

Methods

We retrospectively analyzed prospectively collected data of 292 ischemic stroke patients with large vessel occlusion who underwent EVT at three academic stroke centers in China from January 2019 to February 2022. All patients were above 18 years old and had symptoms onset ≤6 h. A decrease of more than 4 points on the National Institute of Health Stroke Scale (NIHSS) after 24 h compared with admission or an NIHSS of 0 or 1 after 24 h was defined as early neurological improvement (ENI), whereas a lack of such improvement in the NIHSS was defined as a failure of early neurological improvement (FENI). A favorable outcome was defined as a modified Rankin scale (mRS) score of 0-2 after 90 days.

Results

A total of 183 patients were included in the final analyses, 126 of whom had FENI, while 57 had ENI. Favorable outcomes occurred in 80.7% of patients in the ENI group, in contrast to only 22.2% in the FENI group (p < 0.001). Mortality was 7.0% in the ENI group in comparison to 42.1% in the FENI group (p < 0.001). The multiple logistic regression model showed that diabetes mellitus [OR (95% CI), 2.985 (1.070-8.324), p = 0.037], pre-stroke mRS [OR (95% CI), 6.221 (1.421-27.248), p = 0.015], last known well to puncture time [OR (95% CI), 1.010 (1.003-1.016), p = 0.002], modified thrombolysis in cerebral infarction = 3 [OR (95% CI), 0.291 (0.122-0.692), p = 0.005], and number of mechanical thrombectomy passes [OR (95% CI), 1.582 (1.087-2.302), p = 0.017] were the predictors of FENI.

Conclusion

Diabetes mellitus history, pre-stroke mRS, longer last known well-to-puncture time, lack of modified thrombolysis in cerebral infarction = 3, and the number of mechanical thrombectomy passes are the predictors of FENI. Future large-scale studies are required to validate these findings.

Clinical Significance and Influencing Factors of Microvascular Tissue Reperfusion After Macrovascular Recanalization

The relevance of impaired microvascular tissue reperfusion despite successful macrovascular angiographic reperfusion (no-reflow) in acute ischemic stroke (AIS) remains controversial. In this study, we aimed to investigate the impact of tissue optimal reperfusion (TOR) and its influencing factors. From December 1, 2020 to December 1, 2021, AIS patients with successful recanalization (modified Thrombolysis in Cerebral Infarction score [mTICI] ≥ 2b) after mechanical thrombectomy (MT) were retrospectively reviewed. Computed tomography perfusion was performed before and after MT. Successful reperfusion was assessed by TOR, defined as > 90% reduction of the Tmax > 6 s lesion volumes between baseline and early follow-up perfusion profiles. The impact of TOR on functional outcomes after successful recanalization and influencing factors for TOR were both investigated. Sixty-three patients were included, including 44 cases in the TOR group and 19 cases in the non-TOR group. The TOR group had a higher rate of favorable outcome (aOR 4.366, 95%CI 1.159-16.445, p = 0.030) and NIHSS improvement (aOR 5.089, 95%CI 1.340-19.322, p = 0.017) than the non-TOR group. Multivariable logistic regression showed baseline glucose (OR 0.648, 95%CI 0.492-0.854, p = 0.002) and mTICI 2c/3 (OR 10.984, 95%CI 2.220-54.343, p = 0.003) predicted TOR in model 1; in model 2, postoperative glucose (OR 0.468, 95%CI 0.278-0.787, p = 0.004) and mTICI 2c/3 (OR 9.436, 95%CI 1.889-47.144, p = 0.006) were predictive. TOR was strongly associated with good functional outcomes after successful recanalization of MT. Higher mTICI grade and lower perioperative glucose level may predict microvascular tissue reperfusion.

Amide proton transfer imaging in stroke

Amide proton transfer (APT) imaging, a variant of chemical exchange saturation transfer MRI, has shown promise in detecting ischemic tissue acidosis following impaired aerobic metabolism in animal models and in human stroke patients due to the sensitivity of the amide proton exchange rate to changes in pH within the physiological range. Recent studies have demonstrated the possibility of using APT-MRI to detect acidosis of the ischemic penumbra, enabling the assessment of stroke severity and risk of progression, monitoring of treatment progress, and prognostication of clinical outcome. This paper reviews current APT imaging methods actively used in ischemic stroke research and explores the clinical aspects of ischemic stroke and future applications for these methods.

Timing of Direct Oral Anticoagulants for Hemorrhagic Transformation After Endovascular Treatment in Acute Ischemic Stroke

OBJECTIVES

The purpose of this study is to investigate the relationship between the timing of starting direct oral anticoagulants (DOACs) and subsequent clinical outcomes in patients with hemorrhagic transformation (HT) after endovascular treatment (EVT).

MATERIALS AND METHODS

The subjects were patients with acute cardioembolic stroke who underwent EVT and received DOACs in our department from February 2017 to August 2021. Based on CT at 24 h after EVT, the patients were classified using European Collaborative Acute Stroke Study criteria into three groups: no HT, hemorrhagic infarction (HI), and parenchymal hematoma (PH). Outcomes were assessed for incidence of recurrent ischemic stroke (RIS), new intracranial hemorrhage (ICH), and worsened HT associated with DOACs.

RESULTS

Of 111 patients, 29 (26.1%) had HT, including 16 (14.4%) with HI and 13 (11.7%) with PH. The start of DOACs was significantly delayed in the PH group (no HT: 1.0 (1.0-3.0) days vs. HI: 3.0 (2.0-5.0) days vs. PH: 7.0 (7.0-10.0) days, P < 0.01). The incidence of RIS did not differ significantly among the three groups, but tended to be higher in the PH group (no HT: 3.7% vs. HI: 6.3% vs. PH: 15.4%, p = 0.12). There were no cases of new symptomatic ICH. New asymptomatic ICH occurred in 2 cases in the no HT group. Worsened HT after initiation of DOACs did not occur in the HI or PH group.

CONCLUSIONS

The timing of starting DOACs in patients with HT after EVT may be divided by subtypes of HI and PH. In patients with HI, early initiation of DOACs can prevent RIS and is unlikely to cause new ICH or worsened HI. In PH, initiation of DOACs within 14 days appears to be safe and does not exacerbate PH. The later the start of DOACs, the higher the frequency of RIS, so early initiation of DOACs is desirable.

Admission Random Blood Glucose, Fasting Blood Glucose, Stress Hyperglycemia Ratio, and Functional Outcomes in Patients With Acute Ischemic Stroke Treated With Intravenous Thrombolysis

Background

Stress hyperglycemia ratio (SHR), calculated as glucose/glycated hemoglobin, has recently been developed for assessing stress hyperglycemia and could provide prognostic information for various diseases. However, calculating SHR using random blood glucose (RBG) drawn on admission or fasting blood glucose (FBG) could lead to different results. This study intends to evaluate the association between SHR and functional outcomes in patients with acute ischemic stroke (AIS) with recombinant tissue plasminogen activator (r-tPA) intravenous thrombolysis.

Methods

Data from 230 patients with AIS following thrombolytic therapy with r-tPA in the Third Affiliated Hospital of Wenzhou Medical University from April 2016 to April 2019 were retrospectively reviewed. SHR1 was defined as [RBG (mmol/L)]/[HbA1c (%)] and SHR2 was defined as [FBG (mmol/L)]/[HbA1c (%)]. The outcomes included early neurological improvement (ENI), poor function defined as a modified Rankin Scale score (mRS) of 3–6, and all-cause death in 3 months. Multivariable logistic regression was performed to estimate the association between SHR and adverse outcomes.

Results

After adjustment for possible confounders, though patients with AIS with higher SHR1 tend to have a higher risk of poor outcome and death and unlikely to develop ENI, these did not reach the statistical significance. In contrast, SHR2 was independently associated with poor functional outcome (per 0.1-point increases: odds ratios (OR) = 1.383 95% CI [1.147–1.668]). Further adjusted for body mass index (BMI), triglyceride-glucose index (TyG), and diabetes slightly strengthen the association between SHR (both 1 and 2) and adverse outcomes. In subgroup analysis, elevated SHR1 is associated with poor functional outcomes (per 0.1-point increases: OR = 1.246 95% CI [1.041–1.492]) in non-diabetic individuals and the association between SHR2 and the poor outcomes was attenuated in non-cardioembolic AIS.

Conclusion

SHR is expected to replace random or fasting glucose concentration as a novel generation of prognostic indicator and a potential therapeutic target.

Acute Hyperglycemia Exacerbates Hemorrhagic Transformation after Embolic Stroke and Reperfusion with tPA: A Possible Role of TXNIP-NLRP3 Inflammasome

OBJECTIVES

Acute hyperglycemia (HG) exacerbates reperfusion injury after stroke. Our recent studies showed that acute HG upregulates thioredoxin-interacting protein (TXNIP) expression, which in turn induces inflammation and neurovascular damage in a suture model of ischemic stroke. The aim of the present study was to investigate the effect of acute HG on TXNIP-associated neurovascular damage, in a more clinically relevant murine model of embolic stroke and intravenous tissue plasminogen activator (IV-tPA) reperfusion.

MATERIALS AND METHODS

HG was induced in adult male mice, by intraperitoneal injection of 20% glucose. This was followed by embolic middle cerebral artery occlusion (eMCAO), with or without IV-tPA (10 mg/kg) given 3 h post embolization. Brain infarction, edema, hemoglobin content, expression of matrix metalloproteinase (MMP-9), vascular endothelial growth factor A (VEGFA), tight junction proteins (claudin-5, occluding, and zonula occludens-1), TXNIP, and NOD-like receptor protein3 (NLRP3)-inflammasome activation were evaluated at 24 h after eMCAO.

RESULTS

HG alone significantly increased TXNIP in the brain after eMCAO, and this was associated with exacerbated hemorrhagic transformation (HT; as measured by hemoglobin content). IV-tPA in HG conditions showed a trend to decrease infarct volume, but worsened HT after eMCAO, suggesting that HG reduces the therapeutic efficacy of IV-tPA. Further, HG and tPA-reperfusion did not show significant differences in expression of MMP-9, VEGFA, junction proteins, and NLRP3 inflammasome activation between the groups.

CONCLUSION

The current findings suggest a potential role for TXNIP in the occurrence of HT in hyperglycemic conditions following eMCAO. Further studies are needed to understand the precise role of vascular TXNIP on HG/tPA-induced neurovascular damage after stroke.

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.

Drug-Induced Hyperglycemia as a Potential Contributor to Translational Failure of Uncompetitive NMDA Receptor Antagonists

Hyperglycemia is a comorbidity in 60–80% of stroke patients; nevertheless, neuroprotective drugs like NMDA receptor (NMDAR) antagonists are typically assessed in normoglycemic animals at the preclinical stage before they are approved to enter clinical trials. Interestingly, as a possible explanation for the translational failure of NMDAR antagonists, it was recently reported that stroke occurring during nighttime causes smaller infarctions in rodents and therefore has a smaller window for neuroprotection. To investigate why stroke occurring during different circadian phases confers a difference in severity, we reanalyzed the published source data and found that some mice that were used in the daytime have higher blood glucose than mice that were used in the nighttime. We then repeated the experiments but found no difference in blood glucose concentration or infarct volume regardless of the circadian phase during which stroke occurs. On the other hand, induction of hyperglycemia by glucose injection reproducibly increased stroke severity. Moreover, although hyperglycemia increases infarction volume, which presumably would provide a larger window for neuroprotection, uncompetitive NMDAR antagonists were unexpectedly found to exacerbate stroke outcome by worsening hyperglycemia. Taken together, our new data and reanalysis of the published source data suggested that blood glucose during stroke, rather than the circadian phase during which stroke occurs, affects the size of the ischemic infarction; moreover, we have revealed drug-induced hyperglycemia as a potential reason for the translational failure of uncompetitive NMDAR antagonists. Future trials for this class of neuroprotective drugs should monitor patients’ blood glucose at enrollment and exclude hyperglycemic patients.

Comparison of risk scores in predicting symptomatic intracerebral hemorrhage after endovascular thrombectomy

BACKGROUND/PURPOSE

Several risk scores have been developed to predict symptomatic intracerebral hemorrhage (SICH) after acute reperfusion therapy for ischemic stroke. We compared the performance of established risk scores in predicting SICH after EVT under different SICH criteria.

METHODS

A total of 258 patients with anterior circulation large vessel occlusion who received EVT in two medical centers of Taiwan were recruited. Three definitions of SICH, the European Collaborative Acute Stroke Study II (ECASS II), ECASS III, and the Safe Implementation of Thrombolysis in Stroke-Monitoring Study (SITS-MOST), were used. The HAT, SITS-SICH, SEDAN, and TAG risk scores were applied. Logistic regression and area under the receiver operating characteristic curve (AUC) were used to evaluate the performance of each risk model.

RESULTS

In the 258 included patients (mean age, 71.9 ± 11.8 years; men, 48.1%), the observed rates of SICH according to ECASS II, ECASS III, and SITS-MOST criteria were 10.1%, 5.0%, and 4.7%, respectively. Higher glucose level (>160 mg/dL) and unsuccessful recanalization independently predicted SICH under all criteria. Among the different risk scores, only SEDAN and TAG consistently predicted SICH. SEDAN and TAG scores exhibited the highest AUC in predicting SICH for ECASS III (SEDAN 0.72, TAG 0.72) and SITS-MOST (SEDAN 0.73, TAG 0.70) criteria.

CONCLUSION

Among various risk scores, the TAG and SEDAN scores best predict SICH after EVT. Higher glucose level and unsuccessful recanalization, which are included in the TAG and SEDAN scores, are independent risk factors of SICH in the present cohort, highlighting their detrimental effects.

Increased Postoperative Fasting Glucose Is Associated With Unfavorable Outcomes in Patients Treated With Mechanical Thrombectomy Treatment

Background and objective: Hyperglycemia on admission was associated with worse clinical outcomes after mechanical thrombectomy (MT) of acute ischemic stroke (AIS). We evaluated whether increased postoperative fasting glucose (PFG) was also related to poor clinical outcomes in patients who underwent MT treatment.

Methods: Consecutive patients with large vessel occlusion underwent MT in our center were included. Admission glucose and fasting glucose levels after MT treatment were evaluated. Primary outcome was 90-day unfavorable outcomes (modified Rankin Scale score of 3–6). Secondary outcome was the rate of symptomatic intracranial hemorrhage (sICH) after MT treatment. The association of PFG and 90-day clinical outcome after MT treatment was determined using logistic regression analyses.

Results: One hundred twenty seven patients were collected. The median postoperative fasting glucose level was 6.27 mmol/L (IQR 5.59–7.62). Fourteen patients (11.02%) had sICH, and fifty-eight patients (45.67%) had unfavorable outcomes at 90-day after MT. After adjustment for potential confounding factors, PFG level was an independent predictor of 90-day unfavorable outcome (OR 1.265; 95% CI 1.017–1.575; p = 0.035) and sICH (OR 1.523; 95% CI 1.056–2.195; p = 0.024) after MT. In addition, older age, higher baseline NIHSS score, and higher postoperative NLR were also associated with unfavorable outcomes at 90-day after MT treatment.

Conclusions: Increased PFG is associated with unfavorable outcomes at 90-day and an increased risk of sICH in patients underwent MT treatment.

Association of laboratory parameters and genetic polymorphisms with ischemic stroke in Chinese Han population

Numerous genetic polymorphisms and clinical laboratory parameters are associated with ischemic stroke (IS). However, the results of such studies have frequently been inconsistent. The aim of the present study was to evaluate associations between clinical laboratory parameters with genetic polymorphisms that influence the risk of IS in a Chinese Han population. Clinical laboratory parameters were measured by an automatic biochemical analyzer. Genotype and allele frequencies of the polymorphisms angiotensin-converting enzyme (ACE) D/I, methylene tetrahydrofolate reductase (MTHFR) C677T and β-fibrinogen (β-Fg) A/G, 455/148T/C were characterized by restriction fragment length polymorphism-PCR. Furthermore, the gene polymorphisms plasminogen activator inhibitor (PAI)-1-4G/5G and apolipoprotein E (ApoE) ε2,3,4 were characterized by allele-specific PCR. The associations of genotype and allele frequencies of the six risk genes in different groups with clinical laboratory parameters were analyzed by chi-square tests. The distribution maps of the polymorphisms of the six genes and clinical laboratory parameters were compared between a control group of 336 healthy individuals and 762 patients with IS. Certain laboratory parameters were associated with ACE I/D, β-Fg-455 A/G and PAI-1 4G/5G. The D allele of ACE I/D was associated with high levels of total cholesterol and low-density lipoprotein cholesterol (LDL-C). Furthermore, high levels of fasting blood glucose, triglyceride and LDL-C were risk factors for IS. There were significant differences in the genotype frequencies of ACE I/D, β-Fg-455 A/G and β-Fg-148 T/C between the IS and the control group. In conclusion, clinical laboratory parameters were associated with the risk of polymorphisms of IS-related genes. The present results support the determination of a range of control values of clinical laboratory parameters for common genotypes in patients with diabetes and hyperlipidemia as a strategy for the early prevention of IS.

Neuroprotective effect of magnesium supplementation on cerebral ischemic diseases

Ischemic encephalopathy is associated with a high mortality and rate of disability. The most common type of ischemic encephalopathy, ischemic stroke, is the second leading cause of death in the world. At present, the main treatment for ischemic stroke is to reopen blocked blood vessels. However, despite revascularization, many patients are not able to achieve good functional results. At the same time, the strict time window (<4.5 h) of thrombolytic therapy limits clinical application. Therefore, it is important to explore effective neuroprotective drugs for the treatment of ischemic stroke. Magnesium is a natural calcium antagonist, which exerts neuroprotective effects through various mechanisms. However, while most basic studies have shown that magnesium supplementation can help treat cerebral ischemia, intravenous magnesium supplementation in large clinical trials has failed to improve prognosis of ischemic patients. Therefore, we review the basic and clinical studies of magnesium supplementation for cerebral ischemia. According to the route of administration, treatment can be divided into intraperitoneal magnesium supplementation, intravenous magnesium supplementation, arterial magnesium supplementation and intracranial magnesium supplementation. We also summarized the potential influencing factors of magnesium ion intervention in cerebral ischemia injury. Finally, in combination with influencing factors derived from basic research, this article proposes three future research directions, including magnesium supplementation into the circulatory system combined with magnesium supplementation in the lateral ventricle, magnesium supplementation in the lateral ventricle combined with hypothermia therapy, and lateral ventricle magnesium supplementation combined with intracarotid magnesium supplementation combined with selective hypothermia.

Stress hyperglycemia is predictive of worse outcome in patients with acute ischemic stroke undergoing intravenous thrombolysis

No study investigated the possible detrimental effect of stress hyperglycemia on patients affected acute ischemic stroke (AIS) undergoing intravenous thrombolysis (IVT). A new index, the glucose-to-glycated hemoglobin ratio (GAR), has been developed for assessing stress hyperglycemia. We retrospectively analyzed data from a prospectively collected database of consecutive patients admitted to the Udine University Hospital with AIS that were treated with IVT from January 2015 to December 2019. Four hundred and fourteen consecutive patients with AIS undergoing IVT entered the study. The patients were then stratified into four groups by quartiles of GAR (Q1-Q4). The higher GAR index was, the more severe stress hyperglycemia was considered. Prevalence of 3 months poor outcome (37.7% for Q1, 34% for Q2, 46.9% for Q3, and 66.7% for Q4, p for trend = 0.001), 3 months mortality (10.5% for Q1, 7.5% for Q2, 11.2% for Q3, and 27.1% for Q4, p for trend = 0.001), and symptomatic intracranial hemorrhage (0.9% for Q1, 0.9% for Q2, 5.1% for Q3, and 17.7% for Q4, p for trend = 0.001) was significant different among the four groups. AIS patients with severe stress hyperglycemia had a significantly increased risk of 3 months poor outcome (OR 2.43, 95% CI 1.14-5.22, p = 0.02), 3 months mortality (OR 2.38, 95% CI 1.01-5.60, p = 0.04), and symptomatic intracranial hemorrhage (OR 16.76, 95% CI 2.09-134.58, p = 0.008) after IVT. In conclusion, we demonstrated that stress hyperglycemia, as measured by the GAR index, is associated to worse outcome in AIS patients undergoing IVT.

The treament of hyperglycemia in acute ischemic stroke with incretin-based drugs

Stroke is a major cause of mortality and morbidity worldwide. Considerable experimental and clinical evidence suggests that both diabetes mellitus (DM) and post-stroke hyperglycemia are associated with increased mortality rate and worsened clinical conditions in acute ischemic stroke (AIS) patients. Insulin treatment does not seem to provide convincing benefits for these patients, therefore prompting a change of strategy. The selective agonists of Glucagon-Like Peptide-1 Receptors (GLP-1Ras) and the Inhibitors of Dipeptidyl Peptidase-IV (DPP-IVIs, gliptins) are two newer classes of glucose-lowering drugs used for the treatment of DM. This review examines in detail the rationale for their development and the physicochemical, pharmacokinetic and pharmacodynamic properties and clinical activities. Emphasis will be placed on their neuroprotective effects at cellular and molecular levels in experimental models of acute cerebral ischemia. In perspective, an adequate basis does exist for a novel therapeutic approach to hyperglycemia in AIS patients through the additive treatment with GLP-1Ras plus DPP-IVIs.

Comparing the effect of dexmedetomidine and labetalol on hemodynamic variables in patients undergoing microlaryngoscopy

INTRODUCTION

This study was conducted to compare the effect of dexmedetomidine and labetalol on hemodynamic variables in patients undergoing microlaryngoscopy.

MATERIAL AND METHODS

In this randomized clinical trial study 70 patients undergoing microlaryngoscopy were involved. The patients were randomly assigned into two groups. Patients in dexmedetomidine group received 0.5 μg/kg of dexmedetomidine diluted in 100 ml of saline solution and the patients in the second group received 0.25 mg/kg of labetalol before anesthesia induction. At the beginning of the surgery, dexmedetomidine was infused at the dose of 0.4 μg/kg/h in the dexmedetomidine group, and labetalol at the dose of 1.8 mg/kg/h in the labetalol group. Patients' systolic blood pressure, diastolic blood pressure, mean arterial blood pressure and heart rate at different times and anesthesia and surgery duration, recovery time and dose of prescribed propofol were recorded and compared between two groups.

RESULTS

There was a significant difference in mean systolic blood pressure, mean diastolic blood pressure, mean arterial blood pressure and mean heart rate between two groups at different times (p value < 0.05).

CONCLUSION

The results of this study indicated that dexmedetomidine had higher efficacy, compared to labetalol, in reducing diastolic blood pressure, systolic blood pressure, heart rate, and mean arterial blood pressure following microlaryngoscopy.

Erythropoietin Pretreatment Effect on Blood Glucose and Its Relationship With Inflammatory Factors After Brain Ischemic-Reperfusion Injury in Rats

Introduction:

Brain Ichemic-Reperfusion Injury (IRI) activates different pathophysiological processes. It also changes physiological parameters such as Blood Glucose (BG) level. An increase in BG after stroke is associated with poor clinical outcomes. Erythropoietin has been shown to be effective on both reducing inflammation and BG level. Therefore, in this study the erythropoietin pretreatment effect on BG and its relationship with inflammatory markers after brain IRI was investigated.

Methods:

Thirty adult male Wistar rats were randomly divided into 5 groups: sham, control and 3 pretreatment groups: single dose, double dose, and triple dose that received 1000 U/kg of erythropoietin before stroke induction in different times intraperitoneally. A rat model of IRI was established by Middle Cerebral Artery Occlusion (MCAO) for 60 minutes. Infarct volume, neurological defects, Interleukin-1α (IL-1α) and IL-6 serum levels were evaluated 24 hours after reperfusion. Also BG was measured after 1, 6, and 24 hours.

Results:

Single dose of erythropoietin significantly decreased infarct volume and improved neurological defects which was associated with decreased serum level of IL-1α and IL-6 but higher doses of erythropoietin administration had adverse effects on histological, neurological, and inflammatory results. In addition, erythropoietin significantly increased BG in a dose-dependent manner.

Conclusion:

Erythropoietin could reduce brain IRI by reducing inflammation and BG stabilization. The results of the present study demonstrated a relationship between inflammatory factors and hyperglycemia after IRI and suggested that erythropoietin may be useful for preventing brain IRI, but its higher doses should be used with caution due to possible side effects.

Probucol prevents blood-brain barrier dysfunction and cognitive decline in mice maintained on pro-diabetic diet

An emerging body of evidence consistently suggests that compromised blood-brain barrier integrity may be causally associated with cognitive decline induced by type-2 diabetes. Our previous studies demonstrated that selected anti-inflammatory/anti-oxidative agents can preserve the integrity of blood-brain barrier and prevent neuroinflammation in mouse models of dysfunctional blood-brain barrier. Therefore, we have tested whether the previously proven blood-brain barrier protective agent, probucol, can prevent blood-brain barrier breakdown and cognitive decline in a dietary-induced murine model of diabetic insulin resistance. After 6-month chronic ingestion of a diet high in fat and fructose, the mice became insulin resistant. The high-fat and high-fructose-fed mice showed significant cognitive decline assessed by Morris water maze, concomitant with significant elevations in cortical and hippocampal glial acidic fibrillary protein and Fluoro Jade-C staining, indicating heightened neuroinflammation and neurodegeneration, respectively. The integrity of blood-brain barrier in high-fat and high-fructose-fed mice was substantially compromised, and this showed a significant association with heightened neurodegeneration. Co-provision of probucol with high-fat and high-fructose diet completely prevented the cognitive decline and blood-brain barrier dysfunction. Similarly, metformin was able to restore the cognitive function in high-fat and high-fructose-fed mice, while its blood-brain barrier protective effects were modest. These data suggest that probucol may prevent cognitive decline induced by insulin resistance by preserving the integrity of blood-brain barrier, whereas metformin's neuroprotective effects may be mediated through a separate pathway.

Hyperglycemia aggravates decrease in alpha-synuclein expression in a middle cerebral artery occlusion model

Hyperglycemia is one of the major risk factors for stroke. Hyperglycemia can lead to a more extensive infarct volume, aggravate neuronal damage after cerebral ischemia. α-Synuclein is especially abundant in neuronal tissue, where it underlies the etiopathology of several neurodegenerative diseases. This study investigated whether hyperglycemic conditions regulate the expression of α-synuclein in middle cerebral artery occlusion (MCAO)-induced cerebral ischemic injury. Male Sprague-Dawley rats were treated with streptozotocin (40 mg/kg) via intraperitoneal injection to induce hyperglycemic conditions. MCAO were performed four weeks after streptozotocin injection to induce focal cerebral ischemia, and cerebral cortex tissues were obtained 24 hours after MCAO. We confirmed that MCAO induced neurological functional deficits and cerebral infarction, and these changes were more extensive in diabetic animals compared to non-diabetic animals. Moreover, we identified a decrease in α-synuclein after MCAO injury. Diabetic animals showed a more serious decrease in α-synuclein than non-diabetic animals. Western blot and reverse-transcription PCR analyses confirmed more extensive decreases in α-synuclein expression in MCAO-injured animals with diabetic condition than these of non-diabetic animals. It is accepted that α-synuclein modulates neuronal cell death and exerts a neuroprotective effect. Thus, the results of this study suggest that hyperglycemic conditions cause more serious brain damage in ischemic brain injuries by decreasing α-synuclein expression.

RS1 (Rsc1A1) deficiency limits cerebral SGLT1 expression and delays brain damage after experimental traumatic brain injury

Acute cerebral lesions are associated with dysregulation of brain glucose homeostasis. Previous studies showed that knockdown of Na⁺ -D-glucose cotransporter SGLT1 impaired outcome after middle cerebral artery occlusion and that widely expressed intracellular RS1 (RSC1A1) is involved in transcriptional and post-translational down-regulation of SGLT1. In the present study, we investigated whether SGLT1 is up-regulated during traumatic brain injury (TBI) and whether removal of RS1 in mice (RS1-KO) influences SGLT1 expression and outcome. Unexpectedly, brain SGLT1 mRNA in RS1-KO was similar to wild-type whereas it was increased in small intestine and decreased in kidney. One day after TBI, SGLT1 mRNA in the ipsilateral cortex was increased 160% in wild-type and 40% in RS1-KO. After RS1 removal lesion volume 1 day after TBI was reduced by 12%, brain edema was reduced by 28%, and motoric disability determined by a beam walking test was improved. In contrast, RS1 removal did neither influence glucose and glycogen accumulation 1 day after TBI nor up-regulation of inflammatory cytokines TNF-α, IL-1β and IL-6 or microglia activation 1 or 5 days after TBI. The data provide proof of principle that inhibition or down-regulation of SGLT1 by targeting RS1 in brain could be beneficial for early treatment of TBI.

Stroke Outcome and Determinants among Patients with and without Diabetes in a Tertiary Hospital in Ghana

BACKGROUND

Diabetes mellitus, a well-established independent risk factor for stroke, has varied association with stroke outcome from previous studies. This study investigated stroke outcome and determinants among patients with and without diabetes in a tertiary hospital in Ghana.

METHODS

A prospective study conducted among stroke patients with and without diabetes admitted in a Ghanaian tertiary hospital. Baseline clinical and biochemical data were documented. Functional stroke outcome was evaluated at 1, 3, and 6 months after stroke using the modified Rankin Scale.

RESULTS

Number of participants enrolled were 326 and 105 (32.20%) had diabetes. Higher proportions of diabetes patients had poor functional stroke outcome at 1, 3, and 6 months (79%, 75.23%, 73.33%) compared with those without diabetes (70.13%, 65.16, 61.99) (p>0.05). Stroke patients with diabetes had lower survival compared with those without diabetes (p=0.0745). Mortality at 6 months was more likely among ischaemic stroke patients with diabetes compared with those without diabetes (Odds Ratio 2.037; CI: 1.058-3.923). Determinants of poor functional stroke outcome for diabetes patients were older age (Adjusted Odds Ratio (AOR)-1.07; CI-1.03-1.12), female gender (AOR-3.74; CI-1.26-12.65), and pneumonia (AOR-11.32; CI-1.93-220.05) whereas the determinants for those without diabetes were unemployment (AOR-4.19; CI-1.24-19.50), speech abnormalities (AOR-1.99; CI1.08-3.73), and pneumonia (AOR-4.05; CI-1.83-9.77). High fasting plasma glucose (HR-1.15; CI-1.07-1.23), elevated temperature (HR-1.41; CI-1.11-1.79), and pneumonia (HR-2.25; CI-1.44-3.50) were determinants of low survival among all stroke patients.

CONCLUSION

Trends towards poorer functional outcome and reduced survival were found among Ghanaian stroke patients with diabetes compared with those without diabetes. Older age, female gender, pneumonia, elevated temperature, and fasting plasma glucose were determinants of adverse outcome in stroke patients with diabetes.

Impaired fasting glucose is associated with unfavorable outcome in ischemic stroke patients treated with intravenous alteplase

OBJECTIVES

Hyperglycemia on admission and diabetes mellitus type II are associated with unfavorable outcome in stroke patients. We studied whether impaired fasting glucose (IFG) is associated with unfavorable outcome in ischemic stroke patients treated with intravenous alteplase as well and if IFG is a stronger prognostic factor than hyperglycemia on admission.

METHODS

We studied 220 consecutive patients with ischemic stroke treated with intravenous alteplase. In all nondiabetic patients, fasting glucose was determined on day 2-5. IFG was defined as fasting glucose level of ≥ 5.6 mmol/L, hyperglycemia on admission as glucose levels ≥ 7.9 mmol/L. The primary effect measure was the adjusted common odds ratio (acOR) for a shift in the direction of worse outcome on the modified Rankin Scale at 3 months, estimated with ordinal logistic regression, and adjusted for common prognostic factors.

RESULTS

The fasting glucose levels were available in 194 and admission glucose levels in 215 patients. Sixty-three (32.5%) had IFG, 58 (27%) hyperglycemia on admission and 32 (14.6%) pre-existent diabetes. Patients with IFG showed a shift towards worse functional outcome compared with patients with normal fasting glucose levels (acOR 2.77; 95% CI 1.54-4.97), which was stronger than hyperglycemia on admission (acOR 1.75; 95% CI 0.91-3.4).

CONCLUSIONS

IFG is associated with unfavorable outcome after treatment with intravenous alteplase for acute ischemic stroke. IFG predicts unfavorable outcome better than hyperglycemia on admission.

Postoperative survival and early complications after intracranial surgery in dogs

OBJECTIVE

To describe survival and early postoperative outcome after intracranial surgery in dogs.

STUDY DESIGN

Retrospective case series.

ANIMALS

Fifty client-owned dogs that underwent intracranial surgery.

METHODS

Records were searched and analyzed for dogs that underwent intracranial surgery between 2005 and 2015. Signalment, clinical presentation, neurological deficits, concurrent medical conditions, laboratory data, diagnosis, administration of perioperative glucocorticoids or antiepileptic drugs, and specific imaging, surgical, and anesthetic variables were recorded. Risk factors for survival, occurrence of postoperative complications, and hospitalization times were identified with univariate linear and logistic regression, followed by multivariable regression models.

RESULTS

All dogs were recovered with a specific protocol in an intensive care unit. Forty-nine of 50 (98%) dogs survived the immediate postoperative period, and 46 of 50 (92%) survived to discharge. Early postoperative neurological deterioration was seen in 45% (22/49) of dogs, and a postoperative complication was diagnosed in 23 of 49 (47%). Nonneurological postoperative complications were seen in 9 of 49 (18%) dogs; the most common consisted of aspiration pneumonia (6/49, 12%). Among variables associated with outcomes, higher postoperative natremia (P = .023) and prolonged hospitalization (P = .024) were associated with the occurrence of postoperative, nonneurological complications.

CONCLUSION

The short-term survival rate of this population was excellent. About half of the dogs experienced neurologic deterioration and postoperative complications, and most resolved with treatment.

CLINICAL SIGNIFICANCE

In our clinical setting, intracranial surgery in dogs was associated with a high rate of survival and a low rate of severe postoperative complications.

Long-term outcomes in older patients with hyperglycemia on admission for ischemic stroke

AIMS

Evaluate the association between admission blood glucose (ABG) and mortality in older patients with or without diabetes mellitus (DM) hospitalized for acute ischemic stroke (AIS).

METHODS

Observational data of patients ≥65years, admitted for AIS between January 2011 and December 2013. ABG levels were classified to categories: ≤70 (low), 70-110 (normal), 111-140 (mildly elevated), 141-180mg/dl (moderately elevated) and >180mg/dl (markedly elevated). Main outcome was all-cause mortality at the end-of-follow-up.

RESULTS

Cohort included 854 patients, 347 with (mean±SD age 80±8, 44% male), and 507 without DM (mean±SD age 78±8, 53% male). There was a significant interaction between DM, ABG and mortality at end-of-follow-up (p≤0.05). In patients without DM there was a dose-dependent association between ABG category and mortality: adjusted hazard ratios (95% CI) compared to normal ABG were 1.8 (1.2-2.8), 2.9 (1.6-5.2) and 4.5 (2.1-9.7), respectively, for mildly, moderately and markedly elevated ABG. In patients with DM there was no association between ABG and mortality. There was no interaction between DM, ABG and in-hospital mortality or length of stay (LOS). Irrespective of DM status, compared to normal ABG levels, increased ABG category was associated with increased in-hospital mortality: adjusted odds ratios were 3.9 (1.1-13.4), 7.0 (1.8-28.1), and 20.3 (4.6-89.6) with mildly, moderately and markedly elevated ABG, respectively. Mean LOS was 6±5, 7±8, 8±7, and 8±8days, respectively.

CONCLUSION

In older patients without DM hospitalized for AIS, elevated ABG is associated with increased long-term mortality. Irrespective of DM status, elevated ABG was associated with increased in-hospital mortality and LOS.

Blood-brain barrier dysfunction and recovery after ischemic stroke

The blood-brain barrier (BBB) plays a vital role in regulating the trafficking of fluid, solutes and cells at the blood-brain interface and maintaining the homeostatic microenvironment of the CNS. Under pathological conditions, such as ischemic stroke, the BBB can be disrupted, followed by the extravasation of blood components into the brain and compromise of normal neuronal function. This article reviews recent advances in our knowledge of the mechanisms underlying BBB dysfunction and recovery after ischemic stroke. CNS cells in the neurovascular unit, as well as blood-borne peripheral cells constantly modulate the BBB and influence its breakdown and repair after ischemic stroke. The involvement of stroke risk factors and comorbid conditions further complicate the pathogenesis of neurovascular injury by predisposing the BBB to anatomical and functional changes that can exacerbate BBB dysfunction. Emphasis is also given to the process of long-term structural and functional restoration of the BBB after ischemic injury. With the development of novel research tools, future research on the BBB is likely to reveal promising potential therapeutic targets for protecting the BBB and improving patient outcome after ischemic stroke.

Hyperglycemia exacerbates downregulation of dynamin-like protein 1 in ischemic cerebral injury

Ischemic stroke is one of the leading causes of adult disability and death. Hyperglycemia is associated with an increased risk of stroke and poor outcomes after brain injury. Dynamin-like protein I (DLP-1) regulates mitochondrial fission and promotes mitochondrial dynamics. Neurodegenerative diseases are associated with mitochondrial dysfunction, and the downregulation of DLP-1 has been previously identified in a stroke animal model. Here, we investigated the changes in DLP-1 protein expression in an animal model of focal cerebral ischemia with induced hyperglycemia. Streptozotocin (40 mg/kg) was intraperitoneally injected into male rats to induce hyperglycemia, and middle cerebral artery occlusion (MCAO) was surgically induced 4 weeks after streptozotocin treatment. Brain tissue was isolated 24 hours after MCAO, and cerebral cortex samples were used for this study. Proteomics revealed a decrease in DLP-1 expression in MCAO animals when compared with controls, and this downregulation was more prominent in MCAO animals with hyperglycemia. Reverse-transcription polymerase chain reaction and Western blot analyses confirmed that DLP-1 was significantly downregulated in MCAO-injured animals with hyperglycemia compared to those without hyperglycemia. The decrease in DLP-1 indicates mitochondrial morphological changes and dysfunction. Together, these results suggest that the severe decrease of DLP-1 seen after brain injury under hyperglycemic conditions may exacerbate the damage to the brain.

Observation of elevated fasting blood glucose and functional outcome after ischemic stroke in patients with and without diabetes

During May 2015 to October 2016, this prospective study enrolled a total of 438 patients with acute ischemic stroke(AIS), meanwhile, records regarding the severity of initial stroke and neurological outcomes at three months, as well as other examination were completed in patients on admission, as well as the measurement and evaluation of fasting blood glucose(FBG) levels. At admission, the median FBG levels in patients with a minor stroke (n=124), [P<0.001]) was significantly lower than that observed in patients with other degrees of stroke. The poor functional outcome distribution across the FBG quartiles ranged from 13.8 % (first quartile) to 59.6% (fourth quartile), with P <0.001. Compared with the reference category (first quartile), patients in the highest quartile had a relative risk of 3.12 (95% confidence interval [CI], 1.88-6.15; P<0.001) while those in the second and third quartiles had relative risks of 1.76 (95% CI, 1.21-3.03; P=0.035) and 2.23 (95% CI, 1.50-3.69; P=0.010), respectively. Furthermore, in the patients without diabetes, FBG level was observed to be increased and indicated an increased risk of disability (odds ratio [OR]: 1.30 (95%CI 1.13-1.61), P=0.002), however, similar result was not detected in patients with prior diabetes (P=0.089). In conclusion, elevated FBG levels after stroke may suggest poor functional outcome at 3-month in patients without a previous history of diabetes.

Low risk of ICH after reperfusion therapy in acute stroke patients treated with direct oral anti-coagulant

BACKGROUND

The safety of intravenous thrombolysis (IVT) and endovascular therapy (EVT) in patients treated with DOAC is unclear. We investigated whether recanalization therapy in patients treated with DOAC is safe.

METHODS

A nationwide, multicenter, retrospective cohort questionnaire survey was conducted to investigate the: (1) frequency of intracerebral hemorrhage (ICH) after recanalization therapy in patients treated with DOAC; (2) independent factors related to ICH; (3) relationship between last intake time of DOAC and ICH; and (4) comparison of ICH frequency between patients treated with DOAC, vitamin K antagonist (VKA), and no-anticoagulation (no-ACT) (control).

RESULTS

One hundred eighteen stroke centers returned the questionnaire and 100 patients (56 IVT alone, 29 EVT alone, and 15 both IVT and EVT) on DOAC were registered. The frequency of asymptomatic and symptomatic (≥4-point NIHSS score increase) ICH within 24h in DOAC patients were 18% and 2%, and were not different compared with the VKA and no-ACT groups (p=0.728; and p=0.626). On multivariate analysis, systolic blood pressure (OR, 1.04; p<0.001) and blood glucose (OR, 1.02; p=0.019) were independent factors for ICH. Among the 52 patients with a known last intake time of DOAC, the rate of ICH was higher in patients ≤4h from last intake than those >4h (38% vs. 10%, p=0.033).

CONCLUSIONS

Risk of ICH after reperfusion therapy in patients treated with DOAC should be low. Systolic blood pressure, glucose level, and DOAC intake time appear to be factors for ICH.

Strategies for transporting nanoparticles across the blood-brain barrier

The existence of blood-brain barrier (BBB) hampers the effective treatment of central nervous system (CNS) diseases. Almost all macromolecular drugs and more than 98% of small molecule drugs cannot pass the BBB. Therefore, the BBB remains a big challenge for delivery of therapeutics to the central nervous system. With the structural and mechanistic elucidation of the BBB under both physiological and pathological conditions, it is now possible to design delivery systems that could cross the BBB effectively. Because of their advantageous properties, nanoparticles have been widely deployed for brain-targeted delivery. This review paper presents the current understanding of the BBB under physiological and pathological conditions, and summarizes strategies and systems for BBB crossing with a focus on nanoparticle-based drug delivery systems. In summary, with wider applications and broader prospection the treatment of brain targeted therapy, nano-medicines have proved to be more potent, more specific and less toxic than traditional drug therapy.

Strategies to Protect the Brain During Cardiac Surgery

Despite significant advances in cardiopulmonary by pass (CPB) technology, surgical techniques, and anes thetic management, central nervous system (CNS) com plications remain a common and costly problem after CPB. Stroke is often considered a rare and unprevent able complication of cardiac surgery. Recent studies have shown that through the use of echocardiography and historical risk stratification strategies, we can de fine which patients are at substantially greater risk for CNS injury. Through enhanced understanding of the etiology of stroke and perioperative factors, which are associated with potential for neuroprotection or injury extension, there now exists a greater potential than ever to substantially reduce neurological injury associ ated with cardiac surgery. Strategies and theories of stratifying patients at risk and secondarily reducing that risk are described, as well as consideration for early postoperative assessment to allow treatment when events occur.

Increased admission and fasting glucose are associated with unfavorable short-term outcome after intra-arterial treatment of ischemic stroke in the MR CLEAN pretrial cohort

BACKGROUND

Limited data are available on the impact of fasting glucose on outcome after intra-arterial treatment (IAT). We studied whether hyperglycemia on admission and impaired fasting glucose (IFG) are associated with unfavorable outcome after IAT in acute ischemic stroke.

METHODS

Patients were derived from the pretrial registry of the MR CLEAN-trial. Hyperglycemia on admission was defined as glucose>7.8mmol/L, IFG as fasting glucose>5.5mmol/L in the first week of admission. Primary effect measure was the adjusted common odds ratio (acOR) for a shift in the direction of worse outcome on the modified Rankin Scale at discharge, estimated with ordinal logistic regression, adjusted for common prognostic factors.

RESULTS

Of the 335 patients in which glucose on admission was available, 86 (26%) were hyperglycemic, 148 of the 240 patients with available fasting glucose levels (62%) had IFG. Median admission glucose was 6.8mmol/L (IQR 6-8). Increased admission glucose (acOR 1.2, 95%CI 1.1-1.3), hyperglycemia on admission (acOR 2.6, 95%CI 1.5-4.6) and IFG (acOR 2.8, 95%CI 1.4-5.6) were associated with worse functional outcome at discharge.

CONCLUSION

Increased glucose on admission and IFG in the first week after stroke onset are associated with unfavorable short-term outcome after IAT of acute ischemic stroke.

Comprehensive interpretation of hyperglycemia and hyperosmolality on the clinical outcomes among ischemic stroke patients

BACKGROUND

Hyperglycemia and hyperosmolality are associated with poor outcomes among acute ischemic stroke (AIS) patients.

OBJECTIVES

We evaluated the association between hyperglycemia and hyperosmolality, as a combination measure, with poor outcome among AIS patients.

METHODS

We conducted a retrospective study of AIS patients admitted to the study hospital emergency department between January and December 2014. Hyperglycemia was defined as serum glucose >144 mg/dL, and hyperosmolality was defined as a serum osmolality >295 mOsm/kg. After excluding hypoglycemia and hypoosmolality, the enrolled patients were classified into the following 4 subgroups: normoglycemia-normoosmolality, hyperglycemia-normoosmolality (HGNO), normoglycemia-hyperosmolality (NGHO), and hyperglycemia-normoosmolality (HGHO). The primary outcome was poor neurological status at 6 months, which was defined as a modified Rankin scale score ≥2.

RESULTS

Six hundred seven patients were included. The primary outcome was 336 (55.4%), and it was highest in the HGNO group (69.6%, 103/148), followed by the HGHO group (67.9%, 53/78), the NGHO group (57.3%, 43/75) and the normoglycemia-normoosmolality group (44.7%, 137/306). The multivariable logistic regression analysis revealed that HGNO and HGHO remained significant factors, with primary outcomes (adjusted odds ratio, 2.08; 95% confidence interval, 1.16-3.71) and 2.93 (1.45-5.91), respectively), whereas NGHO was not a significant factor. Cases of extremely high sodium levels were few in the NGHO and HGHO groups, whereas considerable cases of extremely high glucose level were observed in the HGHO group.

CONCLUSION

Hyperglycemia was associated with poor outcome, even after excluding the effect of hyperosmolality. However, hyperosmolality without hyperglycemia was not associated with poor outcome. An additive effect, likely reflecting severe hyperglycemia, was observed.

Admission hyperglycemia and outcome after intravenous thrombolysis: is there a difference among the stroke-subtypes?

BACKGROUND

The prognostic influence of hyperglycemia in acute stroke has been well established. While in cortical stroke there is a strong association between hyperglycemia and poor outcome, this relation is less clear in lacunar stroke. It has been suggested that this discrepancy is present among patients treated with intravenous tissue plasminogen activator (tPA), but confirmation is needed.

METHODS

In two prospectively collected cohorts of patient treated with intravenous tPA for acute ischemic stroke, we investigated the effect of hyperglycemia (serum glucose level >8 mmol/L) on functional outcome in lacunar and non-lacunar stroke. Poor functional outcome was defined as modified Rankin Scale score ≥ 3 at 3 months.

RESULTS

A total of 1012 patients was included of which 162 patients (16%) had lacunar stroke. The prevalence of hyperglycemia did not differ between stroke subtypes (22% vs 21%, p = 0.85). In multivariate analysis hyperglycemia was associated with poor functional outcome in non-lacunar stroke (OR 2.1, 95% CI 1.39-3.28, p = 0.001). In patients with lacunar stroke, we did not find an association (OR 1.8, 95% CI 0.62-4.08, p = 0.43).

CONCLUSION

This study confirms a difference in prognostic influence of hyperglycemia between non-lacunar and lacunar ischemic stroke.

Central IGF-I Receptors in the Brain are Instrumental to Neuroprotection by Systemically Injected IGF-I in a Rat Model for Ischemic Stroke

AIM

Insulin-like growth factor I (IGF-I) is a neuroprotective agent in animal models of ischemic stroke. The purpose of this study was to determine whether systemically injected IGF-I exerts its neuroprotective action by binding to IGF-I receptors in the brain after crossing the blood-brain barrier, or via peripheral effects.

METHODS

To differentiate the central effects of IGF-I from systemic effects, ischemic stroke was induced in conscious male Wistar Kyoto rats by the injection of endothelin-1 adjacent to the middle cerebral artery in the right hemisphere, while either the IGF-I receptor antagonist JB-1 or vehicle was introduced into the right lateral ventricle.

RESULTS

Intravenous injection of recombinant human (rh)IGF-I resulted in 50% reduction in infarct size, which was counteracted by the central administration of JB-1. Furthermore, rhIGF-I was detected in both the ischemic and nonischemic hemisphere.

CONCLUSIONS

Systemically injected rhIGF-I passes the blood-brain barrier and protects neurons via IGF-I receptors in the brain in rats with an ischemic stroke.

Chronic type 2 diabetes reduces the integrity of the blood-brain barrier by reducing tight junction proteins in the hippocampus

In the present study, we investigated the effects of type 2 diabetes-induced hyperglycemia on the integrity of the blood-brain barrier and tight junction markers in the rat hippocampus. Forty-week-old diabetic (Zucker diabetic fatty, ZDF) rats and littermate control (Zucker lean control, ZLC) rats were used in this study. We evaluated the integrity of the blood-brain barrier by measuring sodium fluorescein extravasation and blood vessel ultrastructure. In addition, tight junction markers, such as zona occludens-1, occludin and claudin-5, were quantified by western blot analysis. ZDF rats showed significantly increased sodium fluorescein leakage in the hippocampus. Tight junction markers, such as occludin and claudin-5, were significantly decreased in the hippocampi of ZDF rats compared to those of ZLC rats. In addition, ZDF rats showed ultrastructural changes with phagocytic findings in the blood vessels. These results suggest that chronic untreated diabetes impairs the permeability of the hippocampal blood-brain barrier by down-regulating occludin and claudin-5, indicating that chronic untreated diabetes may cause hippocampus-dependent dysfunction.

Postischemic fish oil treatment restores long-term retrograde memory and dendritic density: An analysis of the time window of efficacy

We reported that fish oil (FO) prevented the loss of spatial memory caused by transient, global cerebral ischemia (TGCI), provided the treatment covered the first days prior to and after ischemia. Continuing these studies, trained rats were subjected to TGCI, and FO was administered for 10days, with a time window of efficacy (TWE) of 4, 8 or 12h post-ischemia. Retrograde memory was assessed up to 43days after TGCI. In another experiment, ischemic rats received FO with a 4- or 12-h TWE, and dendritic density was assessed in the hippocampus and cerebral cortex. The brain lipid profile was evaluated in sham-operated and ischemic rats that were treated with FO or vehicle with a 4-h TWE. Ischemia-induced retrograde amnesia was prevented by FO administration that was initiated with either a 4- or 8-h TWE. Fish oil was ineffective after a 12-h TWE. Independent of the TWE, FO did not prevent ischemic neuronal death. In the hippocampus, but not cerebral cortex, TGCI-induced dendritic loss was prevented by FO with a 4-h TWE but not 12-h TWE. The level of docosahexaenoic acid almost doubled in the hippocampus in ischemic, FO-treated rats (4-h TWE). The data indicate that (i) the anti-amnesic effect of FO can be observed with a TWE of up to 8h, (ii) the stimulation of dendritic neuroplasticity may have contributed to this effect, and (iii) DHA in FO may be the main active constituent in FO that mediates the cognitive and neuroplasticity effects on TGCI.

Markers for blood-brain barrier integrity: how appropriate is Evans blue in the twenty-first century and what are the alternatives?

In recent years there has been a resurgence of interest in brain barriers and various roles their intrinsic mechanisms may play in neurological disorders. Such studies require suitable models and markers to demonstrate integrity and functional changes at the interfaces between blood, brain, and cerebrospinal fluid. Studies of brain barrier mechanisms and measurements of plasma volume using dyes have a long-standing history, dating back to the late nineteenth-century. Their use in blood-brain barrier studies continues in spite of their known serious limitations in in vivo applications. These were well known when first introduced, but seem to have been forgotten since. Understanding these limitations is important because Evans blue is still the most commonly used marker of brain barrier integrity and those using it seem oblivious to problems arising from its in vivo application. The introduction of HRP in the mid twentieth-century was an important advance because its reaction product can be visualized at the electron microscopical level, but it also has limitations. Advantages and disadvantages of these markers will be discussed together with a critical evaluation of alternative approaches. There is no single marker suitable for all purposes. A combination of different sized, visualizable dextrans and radiolabeled molecules currently seems to be the most appropriate approach for qualitative and quantitative assessment of barrier integrity.