Treatment of Ischemic Stroke by Atorvastatin-Loaded PEGylated Liposome.

There is insufficient evidence on the effect of nanoparticles, particularly liposomes loaded with a statin, on acute ischemic stroke. We investigated the impact of atorvastatin-loaded PEG (polyethylene glycol) conjugated liposomes (LipoStatin) on the outcomes in rats with cerebral ischemia-reperfusion. PEGylated liposome loaded with atorvastatin was developed as a nanoparticle to specifically accumulate in an ischemic region and release the drug to ameliorate the harmful effects of the stroke. LipoStatin was administered to rats with transient middle cerebral artery occlusion through the tail vein immediately after reperfusion (LipoStatin group). LipoStatin efficiently accumulated at the cerebral ischemic injury site of the rat. The LipoStatin group showed a significantly reduced infarct volume (p < 0.01) in brain micro-MR imaging and improved neurological function recovery compared to the control group (p < 0.05). In addition, markedly improved brain metabolism using fluorine-18 fluorodeoxyglucose micro-PET/CT imaging was demonstrated in the LipoStatin group compared with the control group (p < 0.01). Mechanistically, as a result of evaluation through IL-1 beta, TNF-alpha, ICAM-1, and Iba-1 mRNA expression levels at 5 days after cerebral ischemia, LipoStatin showed significant anti-inflammatory effects. Protein expression of occludin, JAM-A, Caveolin-1, and eNOS by western blot at 3 days and fluorescent images at 7 days showed considerable recovery of blood-brain barrier breakdown and endothelial dysfunction. PEGylated LipoStatin can be more effectively delivered to the ischemic brain and may have significant neuroprotective effects. Thus, PEGylated LipoStatin can be further developed as a promising targeted therapy for ischemic stroke and other major vascular diseases.

Deep learning-based personalised outcome prediction after acute ischaemic stroke.

BACKGROUND: Whether deep learning models using clinical data and brain imaging can predict the long-term risk of major adverse cerebro/cardiovascular events (MACE) after acute ischaemic stroke (AIS) at the individual level has not yet been studied. METHODS: A total of 8590 patients with AIS admitted within 5 days of symptom onset were enrolled. The primary outcome was the occurrence of MACEs (a composite of stroke, acute myocardial infarction or death) over 12 months. The performance of deep learning models (DeepSurv and Deep-Survival-Machines (DeepSM)) and traditional survival models (Cox proportional hazards (CoxPH) and random survival forest (RSF)) were compared using the time-dependent concordance index ([Formula: see text] index). RESULTS: Given the top 1 to all 60 clinical factors according to feature importance, CoxPH and RSF yielded [Formula: see text] index of 0.7236-0.8222 and 0.7279-0.8335, respectively. Adding image features improved the performance of deep learning models and traditional models assisted by deep learning models. DeepSurv and DeepSM yielded the best [Formula: see text] index of 0.8496 and 0.8531 when images were added to all 39 relevant clinical factors, respectively. In feature importance, brain image was consistently ranked highly. Deep learning models automatically extracted the image features directly from personalised brain images and predicted the risk and date of future MACEs at the individual level. CONCLUSIONS: Deep learning models using clinical data and brain images could improve the prediction of MACEs and provide personalised outcome prediction for patients with AIS. Deep learning models will allow us to develop more accurate and tailored prognostic prediction systems that outperform traditional models.

d-dimer Level as a Predictor of Recurrent Stroke in Patients With Embolic Stroke of Undetermined Source.

Background and Purpose: This study aimed to investigate the value of d-dimer levels in predicting recurrent stroke in patients with embolic stroke of undetermined source. We also evaluated the underlying causes of recurrent stroke according to d-dimer levels. Methods: A total of 1431 patients with undetermined source were enrolled in this study and divided into quartiles according to their baseline plasma d-dimer levels. The primary outcome measure was the occurrence of recurrent stroke (ischemic or hemorrhagic) in the year following the stroke event. Results: The risk of recurrent stroke increased significantly with the increasing d-dimer quartile (log-rank P=0.001). Patients in the higher d-dimer quartiles had a higher probability of recurrent embolic stroke because of covert atrial fibrillation, hidden malignancy, or undetermined sources. Most recurrent strokes in Q3 and Q4 were embolic but not in Q1 or Q2. Multivariate analysis revealed that patients in Q3 and Q4 had a significantly increased risk of recurrent stroke compared with those in Q1 (hazard ratio, 3.12 [95% CI, 1.07−9.07], P=0.036; hazard ratio, 7.29 [95% CI, 2.59−20.52], P<0.001, respectively; Ptrend<0.001). Binary analyses showed a significant association between a high d-dimer level above normal range and the risk of recurrent stroke (hazard ratio, 2.48 [95% CI, 1.31−4.70], P=0.005). In subgroup analyses, a high d-dimer level was associated with a significantly higher risk of recurrent stroke in men than in women (P=0.039). Conclusions: Our findings suggest that d-dimer levels can be a useful risk assessment biomarker for predicting recurrent stroke, especially embolic ischemic stroke, in patients with undetermined source.

Brain Activity after Intermittent Hypoxic Brain Condition in Rats.

Hypoxic brain injury is accompanied by a decrease in various functions. It is also known that obstructive sleep apnea (OSA) can cause hypoxic brain injury. This study aimed to produce a model of an intermittent hypoxic brain condition in rats and determine the activity of the brain according to the duration of hypoxic exposure. Forty male Sprague-Dawley rats were divided into four groups: the control group (n = 10), the 2 h per day hypoxia exposure group (n = 10), the 4 h per day hypoxia exposure group (n = 10), and the 8 h per day hypoxia exposure group (n = 10). All rats were exposed to a hypoxic chamber containing 10% oxygen for five days. Positron emission tomography-computed tomography (PET-CT) brain images were acquired using a preclinical PET-CT scanner to evaluate the activity of brain metabolism. All the rats were subjected to normal conditions. After five days, PET-CT was performed to evaluate the recovery of brain metabolism. Western blot analysis and immunohistochemistry were performed with vascular endothelial growth factor (VEGF) and brain-derived neurotrophic factor (BDNF). The mean SUV was elevated in the 2 h per day and 4 h per day groups, and all brain regions showed increased metabolism except the amygdala on the left side, the auditory cortex on the right side, the frontal association cortex on the right side, the parietal association cortex on the right side, and the somatosensory cortex on the right side immediately after hypoxic exposure. However, there was no difference between 5 days rest after hypoxic exposure and control group. Western blot analysis revealed the most significant immunoreactivity for VEGF in the 2, 4, and 8 h per day groups compared with the control group and quantification of VEGF immunohistochemistry showed more expression in 2 and 4 h per day groups compared with the control group. However, there was no significant difference in immunoreactivity for BDNF among the groups. The duration of exposure to hypoxia may affect the activity of the brain due to angiogenesis after intermittent hypoxic brain conditions in rats.

Microbleeds and Outcome in Patients With Acute Ischemic Stroke and Atrial Fibrillation Taking Anticoagulants.

BACKGROUND AND PURPOSE: We investigated the impact of the presence, burden, and location of cerebral microbleeds (CMBs) on the risk of major adverse cerebrovascular and cardiovascular events (MACCE) in patients with acute ischemic stroke and atrial fibrillation treated with oral anticoagulants (OACs). We also examined whether the clinical effect of CMBs differs according to the type of OACs. METHODS: A total of 1742 patients with acute ischemic stroke and atrial fibrillation treated with OACs were enrolled in this cohort study. The primary composite outcome was the occurrence of MACCE (a composite of stroke, acute myocardial infarction, or vascular death) over a 2-year period according to CMB status. RESULTS: CMB presence was significantly associated with the risk of future MACCE (hazard ratio, 1.89 [95% CI, 1.23-2.88]; P=0.003) after adjustment for confounders in patients with acute ischemic stroke and atrial fibrillation taking OACs. Patients with exactly 1 CMB had a similar rate of MACCE compared with those without CMBs (P=0.461). However, patients with multiple CMBs (≥2), particularly high burden CMBs (≥5), had a significantly higher proportion of MACCE. Both CMB-positive groups with lobar and deep CMB had more frequent MACCE than the CMB-negative group, and the rate of MACCE was not different according to CMB location. In patients treated with warfarin, CMB was significantly associated with a risk of MACCE (P=0.002), but not in patients treated with direct OACs (P=0.517). CONCLUSIONS: The study results indicate that the risk of future MACCE increased with increasing CMB burden in patients with AIS and atrial fibrillation taking OACs, while the anatomic location of CMBs did not influence the risk of future MACCE. This risk seemed to be more apparent in patients taking warfarin.

Optimal blood pressure after reperfusion therapy in patients with acute ischemic stroke.

We investigated the relationship between the mean blood pressure (BP) at 24-72 h and the clinical outcomes after acute ischemic stroke (AIS) in patients treated with reperfusion therapy. The primary outcome was measured using the modified Rankin Scale (mRS) at 3 months after AIS, and was based on the mean systolic BP at 24-72 h post-AIS. Favorable outcome was defined as mRS scores of 0-2. A total of 1,540 patients treated with reperfusion therapy were enrolled in the study. Favorable outcomes occurred more frequently in patients with BP ≤ 130/80 mmHg, and the risks of symptomatic intracranial hemorrhage and early neurological deterioration were lower in this optimal BP group. Multivariable analysis showed a significant association between mean BP ≤ 130/80 mmHg at 24-72 h and favorable outcomes at 3 months after AIS (odds ratio 2.95, 95% confidence interval 2.32-3.77, p < 0.001). Prespecified subgroup analyses showed that BP ≤ 130/80 mmHg had a more significant impact on clinical outcome in patients with recanalization than in those without recanalization. These data indicate that a mean BP of ≤ 130/80 mmHg at 24-72 h post-AIS is independently associated with favorable outcomes in patients treated with reperfusion therapy, particularly in those with recanalization.

Impact of Visceral Adipose Tissue on Clinical Outcomes After Acute Ischemic Stroke.

Background and Purpose- The purpose of this study was to investigate the association between adiposity using adipose tissue imaging and stroke outcomes in acute ischemic stroke patients treated with intravenous thrombolysis. Methods- A total of 127 patients with acute ischemic stroke treated with intravenous thrombolysis who underwent abdominal computed tomography on admission were enrolled in this prospective cohort study. Patients were grouped according to their visceral adipose tissue (VAT) proportion tertile. The primary outcome was measured using the modified Rankin Scale 3 months after symptom onset. Favorable and excellent outcomes were defined as modified Rankin Scale scores of 0 to 2 and 0 to 1, respectively. Results- As VAT proportion tertile increased, the number of patients exhibiting a favorable or excellent outcome decreased. In the final multivariable analysis after adjustments for confounders, patients in the highest VAT proportion tertile showed a decreased probability of a favorable and excellent outcome compared with those in the lowest tertile (odds ratio=0.18; 95% CI, 0.05-0.60; P=0.005 and odds ratio=0.13; 95% CI, 0.02-0.64; P=0.012, respectively). Obese patients (body mass index ≥25) also showed an excellent outcome compared with nonobese patients (odds ratio=4.88; 95% CI, 1.47-7.85; P=0.011). Among obese patients, those with an excellent outcome presented a significantly lower VAT proportion than those without (38.2% versus 46.1%, P=0.006). Conclusions- Results of this study indicate that low visceral abdominal fat proportion is associated with a favorable and excellent outcome in acute ischemic stroke patients treated with intravenous thrombolysis. Better clinical outcomes in obese patients were also associated with a lower proportion of VAT.

HbA1c (Glycated Hemoglobin) Levels and Clinical Outcome Post-Mechanical Thrombectomy in Patients With Large Vessel Occlusion.

Background and Purpose- We analyzed the relationship between HbA1c (glycated hemoglobin) levels and clinical outcomes in patients with large vessel occlusion treated with mechanical thrombectomy (MT). Methods- A total of 534 patients with acute ischemic stroke (AIS) treated with MT were enrolled in this prospective cohort study. The primary outcome measured was the modified Rankin Scale score at 3 months, according to HbA1c level. High HbA1c levels were defined as a plasma level of HbA1c >6.5%. Favorable outcomes were defined as functional independence, with modified Rankin Scale scores of 0 to 2. Secondary functional outcomes included mortality, early clinical outcomes, and intracranial hemorrhage. Results- The number of patients with a favorable outcome was significantly lower in patients with HbA1c >6.5% than in those with HbA1c ≤6.5% (28.8% versus 42.1%; P=0.006). In multivariate analysis, high HbA1c levels (especially >7.0% HbA1c) were significantly associated with poor functional outcomes 3 months after AIS in patients with large vessel occlusion treated with MT. High HbA1c was also significantly associated with increased mortality and worse early clinical outcomes after AIS in patients treated with MT. Subgroup analyses showed that HbA1c >6.5% was associated with significantly lower odds of functional independence at 3 months after AIS, when comparing the recanalized group with nonrecanalized patients. Conclusions- These results suggest that high HbA1c level is an independent predictor of a poor outcome at 3 months after AIS in patients with large vessel occlusion treated with MT, particularly in those with recanalization, and may augment the risk of mortality and early clinical worsening after AIS.

Impact of Microbleeds on Outcome Following Recanalization in Patients With Acute Ischemic Stroke.

Background and Purpose- We analyzed the association between cerebral microbleeds (CMBs) and clinical outcome in acute ischemic stroke patients and especially in a subgroup of patients with successful recanalization. Methods- A total of 1532 acute ischemic stroke patients treated with intravenous thrombolysis or mechanical thrombectomy were enrolled in this prospective cohort study. The primary outcome was measured using the modified Rankin Scale at 3 months, according to the CMB status based on magnetic resonance imaging at admission. Favorable outcome was defined as functional independence with modified Rankin Scale scores of 0 to 2. Secondary outcomes included the occurrence of symptomatic intracranial hemorrhage. Results- There was no statistically significant association between the presence of CMB and favorable outcome at 3 months when considering all patients (44.3% versus 37.6%; P=0.121). In patients with recanalization, the number of patients with favorable outcomes was significantly higher in the CMB-negative than in the CMB-positive group (57.0% versus 36.0%; P<0.001). In the final multivariate analysis, the presence of CMB, and in particular high CMB burden (≥5), and lobar location, were significantly associated with less favorable 3-month outcomes (odds ratio=0.57; 95% CI, 0.33-0.97; P=0.038) and symptomatic intracranial hemorrhage (odds ratio=3.21; 95% CI, 1.37-7.49; P=0.007) in patients with recanalization. In the analysis of subgroups, a statistically significant interaction was found between CMB presence and recanalization in predicting functional outcomes at 3 months. Conclusions- These results indicate that the presence of CMBs, and especially high burden and lobar location, are independent predictors of poor 3-month clinical outcomes and may increase symptomatic intracranial hemorrhage risk in acute ischemic stroke patients with recanalization. Our findings suggest that CMBs lead to more unfavorable effects in patients with recanalization after large vessel occlusion than in those without recanalization.

Operation for an anomalous systemic arterial supply to the left lower lobe using an anastomosis procedure in an infant.

An anomalous systemic arterial supply to a normal lung is a rare congenital anomaly, and then for which no standard treatment has been established. We present the case of a 7-month-old girl who had a continuous murmur at the trunk. She was diagnosed the anomalous systemic arterial supply to the left lower lobe, we decided to perform an end-to-side anastomosis between the abnormal systemic artery and left pulmonary artery. After 3 years, the patient showed the normal lung perfusion of the operation lobe.

Overexpression of caveolin-1 attenuates brain edema by inhibiting tight junction degradation.

Cerebral edema from the disruption of the blood-brain barrier (BBB) after cerebral ischemia is a major cause of morbidity and mortality as well as a common event in patients with stroke. Caveolins (Cavs) are thought to regulate BBB functions. Here, we report for the first time that Cav-1 overexpression (OE) decreased brain edema from BBB disruption following ischemic insult. Edema volumes and Cav-1 expression levels were measured following photothrombosis and middle cerebral artery occlusion (MCAO). Endothelial cells that were transduced with a Cav-1 lentiviral expression vector were transplanted into rats. BBB permeability was quantified with Evans blue extravasation. Edema volume was determined from measures of the extravasation area, brain water content, and average fluorescence intensity after Cy5.5 injections. Tight junction (TJ) protein expression was measured with immunoblotting. Cav-1 expression levels and vasogenic brain edema correlated strongly after ischemic insult. Cav-1 expression and BBB disruption peaked 3 d after the MCAO. In addition, intravenous administration of endothelial cells expressing Cav-1 effectively increased the Cav-1 levels 3 d after the MCAO ischemic insult. Importantly, Cav-1 OE ameliorated the vasogenic edema by inhibiting the degradation of TJ protein expression in the acute phase of ischemic stroke. These results suggested that Cav-1 OE protected the integrity of the BBB mainly by preventing the degradation of TJ proteins in rats. These findings need to be confirmed in a clinical setting in human subjects.

Lipoic Acid Use and Functional Outcomes after Thrombolysis in Patients with Acute Ischemic Stroke and Diabetes.

BACKGROUND: Alpha-lipoic acid (aLA) is a strong antioxidant commonly used for treating diabetic polyneuropathy. Previously, we demonstrated the neurorestorative effects of aLA after cerebral ischemia in rats. However, its effects on patients with stroke remain unknown. We investigated whether patients treated with aLA have better functional outcomes after acute ischemic stroke (AIS) and reperfusion therapy than patients not receiving aLA. METHODS: In this retrospective study of 172 prospectively registered patients with diabetes and AIS treated with tissue plasminogen activator (tPA), we investigated the relationship between aLA use and functional outcome both after 3 months and after 1 year. The functional outcomes included occurrence of hemorrhagic transformation (HT), early neurological deterioration (END), and early clinical improvement (ECI). Favorable outcomes were defined as modified Rankin Scale (mRS) scores of 0-2. RESULTS: Of the 172 patients with AIS and diabetes, 47 (27.3%) used aLA. In the entire cohort, favorable outcomes occurred at significantly higher rates both at 3 months and at 1 year in those treated with aLA. The risks for END and HT were lower and the occurrence of ECI was higher in patients treated with aLA. In multivariable analysis, aLA use was associated with favorable outcomes both at 3 months and at 1 year. Age, HT, and increased National Institutes of Health Stroke Scale scores were negative predictors of a favorable outcome. CONCLUSIONS: The use of aLA in patients with AIS and diabetes who are treated with tPA is associated with favorable outcomes. These results indicate that aLA could be a useful intervention for the treatment of AIS after reperfusion therapy.

Regulation of Caveolin-1 Expression Determines Early Brain Edema After Experimental Focal Cerebral Ischemia.

BACKGROUND AND PURPOSE: Most patients with cerebral infarction die of brain edema because of the breakdown of the blood-brain barrier (BBB) in ischemic tissue. Caveolins (a group of proteins) are key modulators of vascular permeability; however, a direct role of caveolin-1 (Cav-1) in the regulation of BBB permeability during ischemic injury has yet to be identified. METHODS: Cav-1 expression was measured by immunoblotting after photothrombotic ischemia. A direct functional role of Cav-1 in cerebral edema and BBB permeability during cerebral ischemia was investigated by genetic manipulation (gene disruption and re-expression) of Cav-1 protein expression in mice. RESULTS: There was a significant correlation between the extent of BBB disruption and the Cav-1 expression. In Cav-1-deficient (Cav-1(-/-)) mice, the extent of BBB disruption after cerebral ischemia was increased compared with wild-type (Cav-1(+/+)) mice, whereas the increase in cerebral edema volume was ameliorated by lentiviral-mediated re-expression of Cav-1. Furthermore, Cav-1(-/-) mice had significantly higher degradation of tight junction proteins and proteolytic activity of matrix metalloproteinase than Cav-1(+/+) mice. Conversely, re-expression of Cav-1 in Cav-1(-/-) mice restored tight junction protein expression and reduced matrix metalloproteinase proteolytic activity. CONCLUSIONS: These results indicate that Cav-1 is a critical determinant of BBB permeability. Strategies for regulating Cav-1 represent a novel therapeutic approach to controlling BBB disruption and subsequent neurological deterioration during cerebral ischemia.