Mediation effect of stroke recurrence in the association between post-stroke interleukin-6 and functional disability.

AIM: Post-stroke inflammation increases the risk of functional disability through enlarged cerebral infarct size directly and follow-up stroke event indirectly. We aimed to use post-stroke proinflammatory cytokine interleukin-6 (IL-6) as a marker of inflammatory burden and quantify post-stroke inflammation's direct and indirect effect on functional disability. METHODS: We analyzed patients with acute ischemic stroke admitted to 169 hospitals in the Third China National Stroke Registry. Blood samples were collected within 24 h of admission. Stroke recurrence and functional outcome measured by the modified Rankin scale (mRS) were assessed via face-to-face interviews at 3 months. Functional disability was defined as an mRS score ≥2. Mediation analyses under the counterfactual framework were performed to examine the potential causal chain in which stroke recurrence may mediate the relationship between IL-6 and functional outcome. RESULTS: Among the 7053 analyzed patients, the median (interquartile range [IQR]) NIHSS score was 3 (1-5), and the median (IQR) level of IL-6 was 2.61 (1.60-4.73) pg/mL. Stroke recurrence was observed in 458 (6.5%) patients, and functional disability was seen in 1708 (24.2%) patients at the 90-day follow-up. Per stand deviation (4.26 pg/mL) increase in the concentration of IL-6 was associated with an increased risk of stroke recurrence (adjusted odds ratio [aOR], 1.19; 95% CI, 1.09-1.29) and disability (aOR, 1.22; 95% CI, 1.15-1.30) within 90 days. Mediation analyses revealed that 18.72% (95% CI, 9.26%-28.18%) of the relationship between IL-6 and functional disability was mediated by stroke recurrence. CONCLUSIONS: Stroke recurrence mediates less than 20% of the association between IL-6 and functional outcome at 90 days among patients with acute ischemic stroke. In addition to typical secondary prevention strategies for preventing stroke recurrence, more attention should be paid to novel anti-inflammatory therapy to improve functional outcomes directly.

Association between high-sensitivity C-reactive protein, functional disability, and stroke recurrence in patients with acute ischaemic stroke: A mediation analysis.

BACKGROUND: Post-stroke inflammation biomarker high-sensitivity C-reactive protein (hsCRP) increases cerebral infarct size and results in functional disability directly, it also contributes to the formation and maturation of atherosclerotic plaques, which increase the risk of stroke recurrence and results in functional disability indirectly. However, no study has quantified how much functional disability was mediated by stroke recurrence. METHODS: Patients with acute ischaemic stroke within 7 days and admitted to 169 hospitals in the Third China National Stroke Registry were analyzed. Blood samples were collected within 24 h of admission. Stroke recurrence and functional disability (defined as a modified Rankin scale score ≥ 2) were assessed via face-to-face interviews at three months. Mediation analysis under the counterfactual framework was performed to examine the potential causal chain in which stroke recurrence may mediate the relationship between hsCRP and functional outcome. Sensitivity analyses were performed across different subgroups and on different scales of hsCRP measurement. FINDINGS: Of the 7603 analyzed patients (mean [SD] age, 62.3 [11.3] years; 2392 [31.5%] women), the median (interquartile range [IQR]) of NIHSS score was 3.0 (1.0-6.0). The median (IQR) level of hsCRP was 1.73 (0.81-4.38) mg/L. A total of 496 (6.5%) cases of stroke recurrence and 1884 (24.8%) cases of functional disability were observed at the 90-day follow-up. Each SD increase in the concentration of hsCRP was associated with an increased risk of stroke recurrence (adjusted odds ratio [aOR], 1.11; 95% CI, 1.04-1.18) and disability (aOR, 1.14; 95% CI, 1.08-1.20) within 90 days. Of 1884 functionally disabled patients, only 16.0 % (n = 302) of patients experienced stroke recurrence before functional disability. Stroke recurrence during follow-up explained 16.52% (95% CI, 5.79%-27.25%) of the relationship between hsCRP and functional disability. Sensitivity analyses in different subgroups and on different scales of hsCRP measurement showed comparable results. INTERPRETATION: Stroke recurrence mediates less than 20% of the association between hsCRP and functional disability at 90 days among patients with acute ischaemic stroke. In addition to typical secondary prevention strategies for preventing stroke recurrence, more attention should be paid to novel anti-inflammatory therapy to improve functional outcomes. FUNDING: Beijing Natural Science Foundation, the National Key R&D Program of China, the National Natural Science Foundation of China, and the Beijing Municipal Science & Technology Commission.

Serum Phosphate and 1-Year Outcome in Patients With Acute Ischemic Stroke and Transient Ischemic Attack.

Objective: To determine the association between serum phosphate level and 1-year clinical outcomes in patients with acute ischemic stroke and transient ischemic attack. Methods: We included 7,353 patients with acute ischemic stroke and transient ischemic attack from the China National Stroke Registry III for analysis. Participants were divided into 4 groups according to serum phosphate quartiles. Composite end point included recurrent stroke, myocardial infarction, other ischemic vascular events, and all-cause mortality. Poor functional outcome is defined as modified Rankin Scale score of 3 to 6. Multivariable Cox regression or logistic regression was used to evaluate the independent association of serum phosphate with 1-year all-cause mortality, recurrent stroke, composite end point and poor functional outcome. Results: The mean age of the included 7,353 patients was 62.5 years, and 68.6% of them were men. Plotting hazard ratios over phosphate levels suggested a U-shaped association especially for recurrent stroke and composite end point, and therefore the third quartile group was set as reference group. Compared with the third quartile of phosphate (1.06-1.20 mmol/L), the adjusted hazard ratios/odds ratios (95% CI) of the lowest quartile (<0.94 mmol/L) were 0.98 (0.67-1.42) for all-cause mortality, 1.31 (1.05-1.64) for stroke recurrence, 1.26 (1.02-1.57) for composite end point, and 1.27 (1.01-1.61) for poor functional outcome, and the adjusted odds ratio of the highest quartile (≥1.2 mmol/L) was 1.40 (1.11-1.77) for poor functional outcome. Conclusions: Serum phosphate may be an independent predictor of stroke recurrence, composite end point and poor functional outcome after ischemic stroke.

Serum calcium and long-term outcome after ischemic stroke: Results from the China National stroke registry III.

BACKGROUND AND AIMS: Serum calcium abnormality is associated with adverse cardiovascular outcomes, but the effects of serum calcium level on stroke outcomes remain unknown. We aimed to assess the relationship between serum calcium level and 1-year outcomes in patients with acute ischemic stroke and transient ischemic attack. METHODS: We included 9375 stroke patients from the China National Stroke Registry III for analysis. Participants were divided into 4 groups according to albumin corrected-calcium quartiles. Composite end point comprised recurrent stroke, myocardial infarction, other ischemic vascular events, and all-cause mortality. Multivariable Cox or logistic regression was used to evaluate the independent association of albumin corrected-calcium with all-cause mortality, recurrent stroke, composite end point, and poor functional outcome (modified Rankin Scale score ≥3). RESULTS: Compared with the lowest calcium quartile (<2.16 mmol/L), the adjusted hazard ratio (95% CI) of the top quartile (≥2.31 mmol/L) was 1.56 (1.11-2.18) for all-cause mortality, 1.06 (0.87-1.28) for recurrent stroke and 1.08 (0.90-1.01) for composite end point, and the adjusted odds ratio for poor functional outcome was 1.18 (0.96-1.44). The addition of serum calcium to conventional risk factors improved risk prediction of all-cause mortality, leading to a small but significant increase in C-statistics and reclassification with non-significant integrated discrimination improvement (C-statistics, p = 0.02; net reclassification index 11.8%, p = 0.038; integrated discrimination improvement 0.08%, p = 0.42). CONCLUSIONS: High serum calcium levels at baseline were associated with all-cause mortality at 1-year after ischemic stroke, suggesting that serum calcium may be a potential prognostic biomarker and therapeutic target for ischemic stroke.

Phosphodiesterase 4D polymorphisms associate with the short-term outcome in ischemic stroke.

It has been demonstrated that phosphodiesterase 4D (PDE4D) genetic polymorphism is associated with ischemic stroke. However, the association between PDE4D gene and prognosis after ischemic stroke remains unknown. We consecutively enrolled ischemic stroke patients admitted to Beijing Tiantan Hospital from October 2009 to December 2013. Clinical, laboratory and imaging data upon admission were collected. All patients were followed up 3 months after stroke onset. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated to assess the associations of genetic polymorphisms with 3-month outcome after ischemic stroke and different subtypes, under various genetic models. A total of 1447 patients were enrolled, and 3-month follow-up data were obtained from 1388 (95.92%). Multivariate regression analysis showed that SNP87 of PDE4D gene was associated with increased risk of unfavorable outcome after total ischemic stroke (OR = 1.47, 95%CI 1.12-1.93), as well as stroke due to large-artery atherosclerosis (OR = 1.49, 95%CI 1.04-2.11) and small-artery occlusion (OR = 1.76, 95%CI 1.05-2.96) under a recessive model. No association between SNP83 genotype and poor outcome was found. Overall, this study demonstrated that the TT genotype of SNP87 in PDE4D was associated with increased risk of poor outcome after total ischemic stroke, large-artery atherosclerosis and small-artery occlusion, in a Chinese population.

Circulating MicroRNAs as potential risk biomarkers for hematoma enlargement after intracerebral hemorrhage.

BACKGROUND AND PURPOSE: MicroRNAs have recently been shown to regulate the downstream bioprocesses of intracerebral hemorrhage. The aim of this study was to investigate whether miRNAs can be used as biomarkers to predict secondary hematoma enlargement (HE) in patients with ICH. METHODS: Consecutively, 79 ICH patients admitted within 6 h of symptom onset and 30 healthy individuals were enrolled in this study. Whole-genome miRNA expression profiles were generated in 32 patients (HE/non-HE: 14/18). Representative differentially expressed miRNAs were measured in all cases (HE/non-HE: 30/49) and normal controls (n = 30) by real-time PCR. RESULTS: Thirty miRNAs showed differential expressions in the plasma samples from patients with HE as compared with the non-HE controls. Compared to the hierarchical cluster analysis with all probes on microarray, all patients were separated into two main branches with only four exceptions by 30 differentially expressed miRNAs, improving the overall accuracy from 47.62 to 77.78% in the HE and 72.73 to 100% in the non-HE group. Further support vector machine (SVM) test can discriminate the two groups with 100% accuracy with 10 differentially expressed miRNAs. CONCLUSIONS: We demonstrated that multiple miRNAs are differentially expressed in the plasma of ICH patients with or without HE and may serve as circulating biomarkers for predicting HE after ICH.

Heterozygote genotypes at rs2222823 and rs2811712 SNP loci are associated with cerebral small vessel disease in Han Chinese population.

AIMS: With developments of etiology of cerebral small vessel disease (CSVD) and genome-wide association study (GWAS) of stroke, the genetic studies of CSVD are focused on genes related to blood-brain barrier (BBB) and aging. The project aims to investigate the association between CSVD and susceptibility loci and candidate genes. METHODS: All study subjects admitted Beijing Tiantan Hospital from June 2009 to September 2010 including 197 cerebral small vessel disease patients(S), 198 large artery atherosclerosis control individuals (vascular stenotic rate ≥50% diameter reduction) (L), 200 hypertensive intracerebral hemorrhage control individuals (H) and 197 stroke-free control individuals (C). 15 SNPs in 4 genes (MYLK, AQP4, NINJ2, and INK4/ARF) were genotyped using Multiplex Snapshot assay. Each SNP was first examined between the groups S and C in different genetic models (codominant, dominant, recessive, overdominant, and log-additive). Permutation correction was used to adjust for multiple testing. The significant SNP loci were further analyzed in comparing S with L and H, respectively. Subgroup analysis was also performed for each risk-factor category. RESULTS: Among the 15 SNPs, rs2222823 and rs2811712 were found to be significantly associated with CSVD after multiple-testing adjustment. The heterozygote (A/T) of rs2222823 of MYLK has an odds ratio of 0.52 (95% CI =[0.35, 0.79], P= 0.002, adjusted P= 0.031) when compared with homozygotes. The heterozygote (C/T) of rs2811712 of INK4/ARF has an odds ratio of 1.75 (95% CI =[1.13-2.71], P= 0.004, adjusted P= 0.050). The SNP rs2222823 was significant (P= 0.035) in comparing S with H. In comparing S versus L, it is significant for the subgroups of patients without diabetes (P= 0.012) and drinking (P= 0.018). rs2811712 was significant in comparing S with L for the subgroups of patients with hyperlipidemia (P= 0.029) and drinking (P= 0.04). CONCLUSION: The heterozygotes (T/A) at the rs2222823 SNP locus of MYLK gene decreases the risk of having cerebral small vessel disease, while the heterozygotes (C/T) at the rs2811712 SNP locus of INK4/ARF gene increases the risk, suggesting that the MYLK and INK4/ARF are the associated genes of cerebral small vessel disease in Han Chinese population.

[Acute dopaminergic responsiveness test in diagnosis of Parkinson's disease and Parkinsonian disorders].

OBJECTIVE: To investigate the features of acute dopaminergic responsiveness test in patients with Parkinsonian disorders, and to find a convenient approach of differential diagnosis of Parkinsonian disorders. METHODS: Sixty inpatients with Parkinson disease (PD) or Parkinson's syndrome, including vascular Parkinsonism (VP), multiple system atrophy (MSA), etc, were given the Levodopa and Benserazide tablets, containing levodopa of the doses of 62.5, 125 187.5, 250, and 375 mg in a pattern of gradual acute DOPA test. The third part of the unified Parkinson's disease rating scale (UPDRS) was used to evaluate the development of PD symptom before and 1 hour after taking the medicine. The differences among the improvement rates were compared with one-way ANOVA test and post hoc multiple comparison by SSPS 11.5. RESULTS: The improvement rates after taking the Levodopa and Benserazide tablets were 11.3% for the dose of 62.5 mg, 23.1% for 125 mg, 29.4% for 187.5 mg, 31.2% for 250 mg, and 34.3% for 375 mg. When the dose was 65 mg there was no significant difference between the diagnoses of PD and Parkinsonism, however, when the doses were 125, 187.5, 250, and 375 mg, and the improvement rates > or = 23.1%, 29.4%, 31.2%, and 34.3% were used as the indicators of diagnosis of PD, there were significant differences between the diagnoses of PD and Parkinson's syndrome. CONCLUSION: Easy and convenient, acute dopaminergic responsiveness test is not associated with sex, age, and H-Y ranking, and is an important approach in differential diagnosis of Parkinsonian disorders.

Small artery dementia in Japan: radiological differences between CADASIL, leukoaraiosis and Binswanger's disease.

CADASIL (cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy) is a hereditary small artery disease which is phenotypically similar to Binswanger's disease (BD), a nonhereditary form of small artery disease. Recent studies have indicated that lesions in the temporopolar, medial frontopolar areas and external capsule are frequently seen in Caucasian patients with CADASIL. However, it remains unclear whether magnetic resonance (MR) imaging findings are helpful in diagnosing small artery disease outside countries with Caucasian populations, since CADASIL is rare despite the high prevalence of small artery disease in Japan. We examined 58 patients with small artery disease, all of whom were devoid of major vessel occlusion or severe stenosis. These patients included 7 patients from 3 families with CADASIL, 27 nondemented patients with extensive leukoaraiosis (LA) and 24 patients with BD. On T(2)-weighted MR images, hyperintensities in the temporopolar areas were observed in all 7 patients with CADASIL, whereas these lesions were observed in only 1 subject from each of the nondemented LA and BD groups. Hyperintensities in the medial frontopolar areas were seen in 4 of the 7 patients with CADASIL (57%) and in 14 of the 24 patients with BD (58%), and were more frequent than in the nondemented LA group (4 of the 27 patients; 15%). In contrast, hyperintensities in the external capsule were frequently observed in all groups. Therefore, temporopolar lesions can also serve as diagnostic markers for CADASIL in non-Caucasian patients.

[Distribution of ischemic leukoaraiosis in MRI: a difference from white matter lesions in CADASIL].

Previously, the distribution of white matter lesions in CADASIL has been reported to be distinct from those in patients with ischemic leukoaraiosis and Binswanger's disease. In earlier European studies, diagnostic significance of white matter lesions in the temporopolar region (Tp), medial frontopolar region (Fp) and external capsule (EC) was stressed in diagnosing CADASIL. More recently, however, high sensitivity and specificity of Tp lesions have been demonstrated. In Japan, prevalence of CADASIL is lower, and those of ischemic leukoaraiosis and Binswanger's disease, likely related to small artery disease, are much higher than in Caucasian countries. Therefore, we examined the frequencies of CADASIL-associated lesions in 17 non-demented patients with ischemic leukoaraiosis and 20 patients with Binswanger's disease. The Binswanger's disease group showed a significantly lower scores for Hasegawa Dementia Rating Scale Revised (HDSR) and a higher prevalence of hypertension, compared to the ischemic leukoaraiosis group. There was only 1 patient with Tp lesions in each group, while Fp lesions were found in 12 % and 50% in the ischemic leukoaraiosis group and Binswanger's disease group, respectively, and EC lesions in 59% and 80%. These results indicated that Tp lesions were useful diagnostic marker in diagnosing CADASIL, whereas Fp and EC lesions were non-specifically observed.

Different mechanisms of corpus callosum atrophy in Alzheimer's disease and vascular dementia.

Previous neuroimaging studies have indicated that corpus callosum atrophy in Alzheimer's disease (AD) and large vessel occlusive disease (LVOD) is caused by interhemispheric disconnection, namely Wallerian degeneration of interhemispheric commissural nerve fibers originating from pyramidal neurons in the cerebral cortex. However, this hypothesis has not been tested from a neuropathological viewpoint. In the present study, 22 brains with AD (presenile onset, 9; senile onset, 13), 6 brains with Binswanger's disease (BD), a form of vascular dementia and 3 brains with LVOD were compared with 6 non-neurological control brains. White matter lesions in the deep white matter and corpus callosum were quantified as a fiber density score by image analysis of myelin-stained sections. Axonal damage and astrogliosis were assessed by immunohistochemistry for amyloid precursor protein and glial fibrillary acidic protein, respectively.The corpus callosum thickness at the anterior part of the body was decreased in AD and LVOD,but not in BD significantly, as compared with the controls. The corpus callosum thickness correlated roughly with brain weight in AD (R=0.50),and with the severity of deep white matter lesions in BD (R=0.81). Atrophy of the brain and corpus callosum was more marked in presenile onset AD than in senile onset AD. With immunohistochemistry, the corpus callosum showed axonal damage and gliosis with a decreased fiber density score in BD and LVOD, but not in AD. Thus, corpus callosum atrophy was correlated with brain atrophy in AD, which is relevant to the mechanism of interhemispheric disconnection,whereas corpus callosum lesions in BD were secondary to deep white matter lesions. Corpus callosum atrophy in LVOD may indicate interhemispheric disconnection, but focal ischemic injuries may also be involved.

Ibudilast, a phosphodiesterase inhibitor, protects against white matter damage under chronic cerebral hypoperfusion in the rat.

Cerebrovascular white matter (WM) lesions, which are frequently observed in vascular cognitive impairment and vascular dementia, can be produced in rats by clipping the common carotid arteries bilaterally. Since TNF-alpha is known to cause the degeneration of myelin, we examined whether these lesions can be ameliorated by ibudilast, a cyclic AMP phosphodiesterase (PDE) inhibitor that suppresses tumor necrosis factor (TNF)-alpha production. After the ligation of both common carotid arteries in 29 rats, 21 rats received a daily oral administration of 10, 30 or 60 mg/kg ibudilast and 8 rats received vehicle for 14 days. The pathological changes in the white matter were quantified in terms of white matter lesions and the emergence of activated microglia immunoreactive for major histocompatibility complex (MHC) antigen. In the vehicle-treated animals, white matter lesions and microglial activation occurred in the optic tract, internal capsule and corpus callosum. A low dose (10 mg/kg) of ibudilast failed to suppress the white matter lesions and microglial activation, whereas a dose of either 30 or 60 mg/kg ibudilast ameliorated these lesions (p<0.001). Without an alterations in laboratory blood data, 60 mg/kg ibudilast exhibited percent reduction of the white matter lesions ranging between 50% and 70%, which was more effective than 30 mg/kg ibudilast (p<0.05). The TNF-alpha immunoreactive glia decreased in number in the 60 mg/kg ibudilast-treated group as compared to the vehicle-treated group (p<0.001). These results indicate a dose-dependent protective effect of ibudilast against cerebrovascular white matter lesions and suggest a potential use for ibudilast in the treatment of vascular dementia.

Axonal damage and demyelination in the white matter after chronic cerebral hypoperfusion in the rat.

Cerebral white matter (WM) lesions are observed frequently in human ischemic cerebrovascular disease and have been thought to contribute to cognitive impairment. This type of lesion can be experimentally induced in rat brains under chronic cerebral hypoperfusion by the permanent occlusion of both common carotid arteries. However, it remains uncertain whether chronic ischemia can damage both the gray and white matter, and whether it can induce demyelination with or without axonal damage. Therefore, we examined axonal damage using immunohistochemistry for the amyloid beta/A4 precursor protein (APP), chromogranin A (CgA) and demyelination using immunohistochemistry for the encephalitogenic peptide (EP) in this model. Severe WM lesions such as vacuolation and the loss of nerve fibers appeared in the optic nerve and optic tract after 3 days of ligation, and less intense changes were observed in the corpus callosum, internal capsule, and fiber bundles of the caudoputamen after 7 days with Klüver-Barrera and Bielschowsky staining. These WM lesions persisted even after 30 days. The APP, CgA, and EP-immunopositive fibers increased in number from 1 to 30 days after the ligation in the following WM regions: the optic nerve, optic tract, corpus callosum, internal capsule, and fiber bundles of the caudoputamen. In contrast, only a few APP, CgA, or EP-immunopositive fibers were detected in the gray matter regions, including the cerebral cortex and hippocampus. These results indicate that the WM is more susceptible to chronic cerebral hypoperfusion than the gray matter, with an involvement of both axonal and myelin components. Furthermore, immunohistochemistry for APP, CgA, and EP is far superior to routine histological staining in sensitivity and may become a useful tool to investigate WM lesions caused by various pathoetiologies.