Safety of Apixaban Monotherapy for Non-Valvular Atrial Fibrillation-Related Acute Stroke with Intra-/Extracranial Artery Stenosis.

INTRODUCTION: We investigated whether apixaban is safe for the prevention of further adverse events in non-valvular atrial fibrillation (NVAF) patients with intra-/extracranial artery stenosis (Stenosis group) compared with acute large vessel occlusion without intra-/extracranial artery stenosis (No stenosis group). We also examined whether combination therapy using apixaban and antiplatelet is safe. METHODS: ALVO (Apixaban on clinical outcome of patients with Large Vessel Occlusion [LVO] or stenosis) was a historical and prospective multicenter registry at 38 centers in Japan. Patients with NVAF and acute LVO or stenosis who received apixaban within 14 days after onset were included. We conducted the post hoc analysis using the ALVO dataset. We compared patients with stenosis versus those without stenosis in terms of the primary outcome, which was defined as a composite of all-cause death, major bleeding events, and ischemic events 365 days after onset. RESULTS: Of the 662 patients, 54 (8.2%) patients were classified into the Stenosis group, and 104 patients of the total (16%) reached the primary outcome. The cumulative incidence of primary outcome was not significantly different between the No stenosis and the Stenosis groups (hazard ratio [HR] 1.2, 95% confidence interval [CI]: 0.64-2.4; p = 0.52). Even after adjustment for predictive clinical variates, no significant difference in the primary endpoint between the No stenosis and the Stenosis groups was shown (adjusted HR 1.2, 95% CI: 0.59-2.5; p = 0.60). Fifty patients (7.6%) used an antiplatelet with apixaban. Among the Stenosis group patients, the cumulative incidence of the primary outcome was significantly higher among patients treated with an antiplatelet and apixaban (HR 3.5, 95% CI: 1.0-12; p = 0.048). CONCLUSION: Apixaban monotherapy appears safe for the prevention of further adverse events in the Stenosis group patients similar to the No stenosis group patients. Concomitant use of an antiplatelet might not be favorable in patients with stenosis.

Endovascular vs Medical Management for Late Anterior Large Vessel Occlusion With Prestroke Disability: Analysis of CLEAR and RESCUE-Japan.

BACKGROUND AND OBJECTIVES: Current guidelines do not address recommendations for mechanical thrombectomy (MT) in the extended time window (>6 hours after time last seen well [TLSW]) for large vessel occlusion (LVO) patients with preexisting modified Rankin Scale (mRS) > 1. In this study, we evaluated the outcomes of MT vs medical management in patients with prestroke disability presenting in the 6- to 24-hour time window with acute LVO. METHODS: We analyzed a multinational cohort (61 sites, 6 countries from 2014 to 2020) of patients with prestroke (or baseline) mRS 2 to 4 and anterior circulation LVO treated 6-24 hours from TLSW. Patients treated in the extended time window with MT vs medical management were compared using multivariable logistic regression and inverse probability of treatment weighting (IPTW). The primary outcome was the return of Rankin (ROR, return to prestroke mRS by 90 days). RESULTS: Of 554 included patients (448 who underwent MT), the median age was 82 years (interquartile range [IQR] 72-87) and the National Institutes of Health Stroke Scale (NIHSS) was 18 (IQR 13-22). In both MV logistic regression and IPTW analysis, MT was associated with higher odds of ROR (adjusted OR [aOR] 3.96, 95% CI 1.78-8.79 and OR 3.10, 95% CI 1.20-7.98, respectively). Among other factors, premorbid mRS 4 was associated with higher odds of ROR (aOR, 3.68, 95% CI 1.97-6.87), while increasing NIHSS (aOR 0.90, 95% CI 0.86-0.94) and decreasing Alberta Stroke Program Early Computed Tomography Scale score (aOR per point 0.86, 95% CI 0.75-0.99) were associated with lower odds of ROR. Age, intravenous thrombolysis, and occlusion location were not associated with ROR. DISCUSSION: In patients with preexisting disability presenting in the 6- to 24-hour time window, MT is associated with a higher probability of returning to baseline function compared with medical management. CLASSIFICATION OF EVIDENCE: This investigation's results provide Class III evidence that in patients with preexisting disability presenting 6-24 hours from the TLSW and acute anterior LVO stroke, there may be a benefit of MT over medical management in returning to baseline function.

Reperfusion Therapy Brings Apixaban Administration Forward in Patients with Nonvalvular Arterial Fibrillation with Anterior Circulation Large Vessel Occlusion or Stenosis.

OBJECTIVE: The initiation of anticoagulant administration after large vessel occlusion (LVO) or stenosis with nonvalvular arterial fibrillation (NAVF) is controversial. We evaluate the timing of anticoagulation and its relationship with clinical factors. METHODS: We enrolled 595 anterior circulation LVO or stenosis with NAVF cases from 38 stroke centers. Laboratory data; activities of daily living; the Alberta Stroke Program Early CT Score (ASPECTS); the National Institutes of Health Stroke Scale (NIHSS) score; occluded artery; treatment methods; date of the initiation of apixaban administration and outcome were recorded. Multivariate analyses were performed after univariate analysis. RESULTS: The median start of apixaban administration after the stroke was 2 days (interquartile range, 1-5; range, 0-14). Multivariate analysis of variance showed that non-internal carotid artery occlusion (F value 4.60), reperfusion therapy (31.1), high ASPECTS (6.27) before anticoagulant intake, and absence of intracranial hemorrhage (12.9) were significantly correlated with early apixaban administration. Multiple logistic regression analysis for independent living at 90 days after the stroke showed significant factors: aging (odds, 0.94; 95% confidence interval [CI], 0.91-0.97); male (odds, 0.46; 95% CI, 0.26-0.79); prestroke independence (odds, 20.7; 95% CI, 6.48-93.9); number of white blood cells (odds, 0.99; 95% CI, 0.97-1.00); non-internal carotid artery occlusion; NIHSS score at 72 hours after the stroke (odds 0.92; 95% CI, 0.89-0.96); ASPECTS before apixaban intake (odds, 1.15; 95% CI, 1.00-1.31) and initiation of apixaban (odds, 0.91; 95% CI, 0.83-0.99). CONCLUSIONS: Early administration of apixaban is induced by nonsevere infarction, reperfusion therapy or none of intracranial hemorrhage and it correlates with an independent long-term outcome.

Effect of prior antiplatelet therapy on large vessel occlusion in patients with non-valvular atrial fibrillation newly initiated on apixaban.

INTRODUCTION: We evaluated the effect of prior antiplatelet therapy on large vessel occlusion (LVO) in patients with non-valvular atrial fibrillation (NVAF) newly initiated on apixaban. METHODS: Patients with acute LVO with acute stroke due to NVAF or stenosis with NVAF started on apixaban within 14 days of onset were enrolled. We compared incidence of major bleeding, cerebral hemorrhage, ischemic events, cerebral infarction, and all-cause mortality between patients with and without prior antiplatelet therapy for acute LVO. We also compared these events between patients who continued antiplatelet therapy after onset (continued group) and those who discontinued it (discontinued group). Hazard ratios were estimated after adjusting for confounders; interaction was evaluated considering intravenous thrombolysis (IVT) or endovascular treatment (EVT) according to major bleeding. RESULTS: The study comprised 686 eligible patients (excluded [n = 194]; enrolled [n = 492]). The antiplatelet group consisted of older patients (mean: 79 vs. 76 years; p = 0.006) and had a higher cumulative incidence of major bleeding (7.3% vs. 2.9%, p = 0.003). The incidence of ischemic events and all-cause mortality was similar between the groups. Among the 109 patients in the antiplatelet group, the cumulative incidence of major bleeding, ischemic events, and all-cause mortality was comparable between continued group (n = 26) and discontinued group (n = 83). There were no significant differences between groups with and without IVT/EVT. However, major bleeding occured more frequently in the antiplatelet group without IVT. CONCLUSION: Prior antiplatelet therapy for LVO in patients with NVAF newly initiated on apixaban was associated with major bleeding, which was more frequent in the antiplatelet group without IVT.

Clinical Trial of the New Stent Retriever Tron FX for both Proximal and Distal Intracranial Large Vessel Occlusions.

BACKGROUND: In all of randomized controlled trials of mechanical thrombectomy, the target vessels were proximal. Herein we report a clinical trial of the Tron FX stent retriever, including the smallest size of 2/15 mm for distal intracranial large vessel occlusion (LVO). OBJECTIVE: Eligible patients presented within 8 h of onset with proximal or distal LVOs, and the Tron FX 4/20 mm or 2/15 mm were used as the first-line device. METHODS: The primary endpoints were rate of modified Thrombolysis in Cerebral Infarction (mTICI) grade 2a-3 immediately after using Tron FX only, and mortality rate 90 d. We compared the outcomes between sizes 4/20 and 2/15 mm. RESULTS: The clinical trial was conducted in 50 cases, of which 44% presented with distal LVO and 15 cases were treated using only Tron FX 2/15 mm. The overall rate of mTICI grade 2a-3 was 80.0% (75.8% with Tron FX 4/20 mm, and 86.7% with 2/15 mm), and a 90-day modified Rankin Scale ≤ 2 or improvement of National Institute of Health Stroke Scale after thrombectomy ≥ 10 was achieved in 66.7% of cases (61.3% with Tron FX 4/20 mm, and 80.0% with 2/15 mm). The overall 90-day mortality rate was 8.0%, and symptomatic intracranial hemorrhage within 24 h occurred in 2.0% of cases. CONCLUSION: In this clinical trial using the Tron FX, which included the size of 2/15 mm for distal LVO, its efficacy was similar and its safety was superior compared with previous studies.

Safety of Early Administration of Apixaban on Clinical Outcomes in Patients with Acute Large Vessel Occlusion.

Early administration of direct oral anticoagulants in patients with acute large vessel occlusion (LVO) and nonvalvular atrial fibrillation (NVAF) is a concern, as endovascular therapy (EVT) became highly utilized. We conducted a historical and prospective multicenter registry at 38 centers in Japan from July 2016 to February 2018. Patients aged ≥ 20 years with NVAF and acute LVO or stenosis who received apixaban within 14 days from onset were included. We compared patients who received apixaban < 48 h (Early group) and ≥ 48 h (Late group) after onset in terms of the primary outcome (a composite of ischemic events, major bleeding events, and all-cause deaths). The secondary outcomes were each component of the primary outcome. Among the 686 patients, the median time from onset to administration was 2.5 days (range, 0-14; Early 263, Late 423). The Alberta Stroke Program Early CT Score (ASPECTS) and diffusion-weighted imaging (DWI)-ASPECTS) were significantly higher in the Early group than in the Late group. Recombinant tissue plasminogen activator (rt-PA) and EVT were more utilized in the Early group (rt-PA 46% vs. 35%, p = 0.003; EVT 62% vs. 46%, p < 0.0001). The cumulative incidence of primary outcome was similar between groups (ischemic events: Early 1.9% vs. Late 0.5% at 30 days; 3.5% vs. 0.7% at 90 days, major bleeding 3.4% vs. 2.9% at 30 days; 5.0% vs. 3.4% at 90 days). Early administration of apixaban (< 48 h), after onset of acute LVO in patients with NVAF, was generally safe compared with those who received it Late (≥ 48 h). http://www.clinicaltrials.gov . Unique identifier: NCT02818868 (June 30, 2016).

Tumor Embolism Through Right-to-Left Shunt Due to Venous Invasion of Esophageal Carcinoma.

A 69-year-old man was admitted to the hospital with right hemiparesis and global aphasia. Perfusion computed tomography imaging revealed ischemic penumbra in the middle cerebral artery territory. Angiography showed left middle cerebral artery occlusion. Mechanical thrombectomy with one pass was performed, and successful recanalization was obtained. Embolic material was retrieved; it contained tumor fragments with atypical keratinizing squamous cell carcinoma. Contrast computed tomography imaging indicated tumor invasion into the superior vena cava, and contrast transcranial Doppler indicated the presence of a right-to-left shunt after the Valsalva maneuver. We diagnosed the patient with acute ischemic stroke of large vessel occlusion due to venous invasion of esophageal carcinoma via a right-to-left shunt. To the best of our knowledge, this is the first case of embolic occlusion resulting from an extracardiac tumor via a right-to-left shunt. Contrast transcranial Doppler potentially detects right-to-left shunts in patients who cannot undergo transesophageal echocardiography.

Aseptic Meningitis as an Initial Manifestation of Anti-myelin Oligodendrocyte Glycoprotein Antibody-associated Disease.

Antibody against myelin oligodendrocyte glycoprotein (MOG-IgG) associated encephalitis is an important syndrome associated with MOG-IgG. However, there have been no reports of MOG-IgG-associated optic neuritis or demyelination following meningitis without encephalitic symptoms. A 55-year-old woman presented to our hospital with headache, nausea, fever, and nuchal rigidity that had persisted for more than a month. She was hospitalized due to aseptic meningitis and recovered with conservative therapy. However, she was re-admitted due to left optic neuritis and demyelinating lesions. We diagnosed MOG-IgG-associated neuromyelitis optica spectrum disorder (NMOSD). She responded to treatment with intravenous methylprednisolone and oral prednisolone. Aseptic meningitis may be an initial manifestation of MOG-IgG-positive NMOSD.

Erythrocyte-Rich Thrombus Is Associated with Reduced Number of Maneuvers and Procedure Time in Patients with Acute Ischemic Stroke Undergoing Mechanical Thrombectomy.

BACKGROUND: Only few studies have investigated the relationship between the histopathology of retrieved thrombi and clinical outcomes. This study aimed to evaluate thrombus composition and its association with clinical, laboratory, and neurointerventional findings in patients treated by mechanical thrombectomy due to acute large vessel occlusion. METHODS: At our institution, 79 patients were treated by mechanical thrombectomy using a stent retriever and/or aspiration catheter between August 2015 and August 2016. The retrieved thrombi were quantitatively analyzed to quantify red blood cells, white blood cells, and fibrin by area. We divided the patients into two groups - a fibrin-rich group and an erythrocyte-rich group - based on the predominant composition in the thrombus. The groups were compared for imaging, clinical, and neurointerventional data. RESULTS: The retrieved thrombi from 43 patients with acute stroke from internal carotid artery, middle cerebral artery, or basilar artery occlusion were histologically analyzed. Erythrocyte-rich thrombi were present in 18 cases, while fibrin-rich thrombi were present in 25 cases. A cardioembolic etiology was significantly more prevalent among the patients with fibrin-rich thrombi than among those with erythrocyte-rich thrombi. Attenuation of thrombus density as shown on computed tomography images was greater in patients with erythrocyte-rich thrombi than in those with fibrin-rich thrombi. All other clinical and laboratory characteristics remained the same. Patients with erythrocyte-rich thrombi had a smaller number of recanalization maneuvers, shorter procedure times, a shorter time interval between arrival and recanalization, and a higher percentage of stent retrievers in the final recanalization procedure. The occluded vessels did not differ significantly. CONCLUSIONS: In this study, erythrocyte-rich thrombus was associated with noncardioembolic etiology, higher thrombus density, and reduced procedure time.

Multiple Cerebral Infarctions Due to Patent Foramen Ovale in a Patient with Eosinophilic Granulomatosis with Polyangiitis.

A 51-year-old man was diagnosed with eosinophilic granulomatosis with polyangiitis 6 years ago due to asthma, sinusitis, hypereosinophilia, and peripheral neuropathy based on the diagnostic criteria of American College of Rheumatology, and corticosteroid therapy achieved a remission. One year ago, he was hospitalized due to deep venous thrombosis (DVT) and pulmonary embolism, and rivaroxaban was administrated. He was admitted to our hospital for acute onset of diplopia and right hemiparesis. Peripheral blood examinations disclosed leukocytosis with hypereosinophilia. Perinuclear anti-neutrophil cytoplasmic antibodies were positive. Diffusion-weighted imaging showed multiple fresh ischemic lesions. Chronic ischemic lesions were seen in subcortical cerebral region. No stenosis or occlusion was shown in extracranial and intracranial arteries on magnetic resonance angiography. Ultrasonography of leg vein showed DVT. Right-to-left shunt through patent foramen ovale after Valsalva maneuver was seen on transesophageal echocardiography. Treatment with corticosteroid and cyclophosphamide alleviated clinical deterioration. Rivaroxaban was changed to warfarin. Diplopia and muscle strength of right limbs were improved. This is a first case of multiple cerebral infarction caused by paradoxical embolism due to patent foramen ovale with DVT based on hypercoagulable state of hypereosinophilia. Overall this case illustrates that eosinophilic granulomatosis with polyangiitis can be a risk factor for multiple cerebral infarction in the systemic phase and that transesophageal echocardiography and ultrasonography of leg vein should be conducted in stroke patient with eosinophilic granulomatosis with polyangiitis.

The Safety of Carotid Artery Stenting for Patients in the Acute Poststroke Phase.

BACKGROUND: The efficacy of carotid artery stenting (CAS) for patients in the acute poststroke phase has not been established. We investigated the outcome of CAS for patients with symptomatic internal carotid artery (ICA) stenosis in the acute poststroke phase. METHODS: We performed a retrospective analysis of all patients who underwent CAS for symptomatic ICA stenosis in our institution. Patients in whom the time interval between neurological deterioration and the CAS procedure was less than 3 days were included in the early group, and the other patients were included in the delayed group. Perioperative complications including major adverse events (MAEs) were compared between the early and the delayed groups. RESULTS: One hundred five patients were included in the study. Forty patients were assigned to the early group and 65 patients were assigned to the delayed group. The overall MAE rate was 4.8%. There was no significant increase in the perioperative MAE in the early group compared with the delayed group (early group 2.5% versus delayed group 6.5%, P = .65). In the early group, 25 of 40 patients (62.5%) were functionally independent (modified Rankin scale [mRS] score of 0-2) at discharge. Significant differences between the independent patients and the disabled patients (mRS score of 3-6) included age (independent 72 versus disabled 79, P < .01) and prevalence of transient ischemic attack (36.0% versus .0%, P = .02). CONCLUSIONS: CAS performed within 3 days from the last ischemic event did not increase the risk of perioperative complication. Early CAS may be a useful option for the treatment of symptomatic carotid artery stenosis.

Cholesterol Crystals in Embolic Debris are Associated with Postoperative Cerebral Embolism after Carotid Artery Stenting.

OBJECT: We investigated possible associations among the presence of cholesterol crystals in embolic debris, the proportions of debris components, and postoperative cerebral embolism in patients undergoing carotid artery stenting (CAS). METHODS: Sixty-seven consecutive procedures were performed for internal carotid artery stenosis with CAS at our hospital between November 2015 and February 2018. Procedures for emergency CAS for stroke in evolution or crescendo transient ischemic attack were excluded (n = 12). The embolic debris from remaining procedures (n = 55) was stained with hematoxylin-eosin and the red blood cells, white blood cells, and fibrin were quantified by color-based segmentation. Cholesterol crystals and calcification were examined histopathologically. Diffusion-weighted imaging (DWI) was performed 1-3 days after CAS, and the images were used to classify procedures according to the presence of new lesions. RESULTS: Of the 55 CAS procedures, new DWI lesions were identified after 32. One patient had symptomatic cerebral embolism. Higher proportions of patients with cholesterol crystals in embolic debris (17 vs. 78%, p < 0.001) and higher proportion of white blood cells (mean 2.3 [0-9.9] vs. 4.2% [0-29.9%], p < 0.01) were observed in the embolic debris of procedures with and without new DWI lesions. CONCLUSIONS: Cholesterol crystals were common in the embolic debris from patients with postoperative ischemic lesions after CAS. These results suggest that inflammatory destabilization of the intraplaque lipid component is related to postprocedural DWI lesions.

[A case of adult-onset type II citrullinemia (CTLN2) triggered by an overseas travel].

A 43-year-old male presented with abnormal behavior and consciousness disturbance on the day after traveling abroad and was admitted to our hospital. Laboratory tests showed hyperammonemia and hypercitrullinemia. The electro-encephalogram showed frontal dominant bilateral slow δ burst. He had a peculiar taste for nuts. But he didn't take nuts during the overseas travel for 3 days. The family history revealed that his younger brother died of a status epilepticus of unknown cause at the age of 29. These findings were compatible with hepatic encephalopathy due to adult-onset type II citrullinemia (CTLN2). Gene analysis provided a definite diagnosis of CTLN2. Diet and drug therapy have improved his condition. He is due to have liver transplantation which is the only established radical treatment for CTLN2 if his condition becomes worse. The present case shows that cessation of the habitual intake of nuts only for 3 days could lead to onset of CTLN2.

Inflammatory biomarkers in atherosclerosis: pentraxin 3 can become a novel marker of plaque vulnerability.

Inflammation is crucially involved in the development of carotid plaques. We examined the relationship between plaque vulnerability and inflammatory biomarkers using intraoperative blood and tissue specimens. We examined 58 patients with carotid stenosis. Following carotid plaque magnetic resonance imaging, 41 patients underwent carotid artery stenting (CAS) and 17 underwent carotid endarterectomy (CEA). Blood samples were obtained from the femoral artery (systemic) and common carotid artery immediately before and after CAS (local). Seventeen resected CEA tissue samples were embedded in paraffin, and histopathological and immunohistochemical analyses for IL-6, IL-10, E-selectin, adiponectin, and pentraxin 3 (PTX3) were performed. Serum levels of IL-6, IL-1ß, IL-10, TNFα, E-selectin, VCAM-1, adiponectin, hs-CRP, and PTX3 were measured by multiplex bead array system and ELISA. CAS-treated patients were classified as stable plaques (n = 21) and vulnerable plaques (n = 20). The vulnerable group showed upregulation of the proinflammatory cytokines (IL-6 and TNFα), endothelial activation markers (E-selectin and VCAM-1), and inflammation markers (hs-CRP and PTX3) and downregulation of the anti-inflammatory markers (adiponectin and IL-10). PTX3 levels in both systemic and intracarotid samples before and after CAS were higher in the vulnerable group than in the stable group. Immunohistochemical analysis demonstrated that IL-6 was localized to inflammatory cells in the vulnerable plaques, and PTX3 was observed in the endothelial and perivascular cells. Our findings reveal that carotid plaque vulnerability is modulated by the upregulation and downregulation of proinflammatory and anti-inflammatory factors, respectively. PTX3 may thus be a potential predictive marker of plaque vulnerability.

[Case of ipsilateral monoparesis by lacunar infarction: a consideration on the pathological mechanism].

An 81-year-old man had sudden-onset dysarthria and weakness in the right leg, and was admitted to our hospital in July 2009. Neurological examination showed right leg monoparesis, sensory disturbance on the right limbs, dysarthria, and decreased deep tendon reflexes. Brain MRI revealed an acute lacunar infarction in the right corona radiata and an old lacunar infarction in the left centrum semiovale, which occurred 4 years before. MR tractography disclosed impaired motor fibers in the right corona radiata, and transcranial magnetic stimulation (TMS) suggested diminished innervation from the bilateral cerebral cortices to the right leg. These results collectively indicated that reorganization of the pyramidal fibers were responsible for the monoparesis ipsilateral to the lacunar infarction, although anomalous pyramidal fibers with ipsilateral innervation were responsible for ipsilateral hemiplegia a previous study.

Chronic cerebral hypoperfusion accelerates amyloid beta deposition in APPSwInd transgenic mice.

Chronic cerebral ischemia may accelerate clinicopathological changes in Alzheimer's disease. We have examined whether chronic cerebral hypoperfusion accelerates amyloid beta deposition in amyloid protein precursor transgenic (APP-Tg) mouse. At 5, 8, and 11 months of age, C57Bl/6J male mice overexpressing a mutant form of the human APP bearing the both Swedish (K670N/M671L) and the Indiana (V717F) mutations (APPSwInd) and their litterrmates were subjected to either sham operation or bilateral carotid artery stenosis (BCAS) using microcoils with an internal diameter of 0.18 mm (short-period group). One month after the sham operation or BCAS, these animals were examined by immunohistochemistry for glial fibrillary acidic protein, amyloid beta(1-40) (Abeta(1-40)), amyloid beta(1-42) (Abeta(1-42)), as well as Western blotting and filter assay for Abeta. Another batch of the littermates of APPSwInd mice were subjected to either sham operation or BCAS at 3 months and were examined in the same manner after survival for 9 months (long-period group). In the BCAS-treated group, the white matter was rarefied and astroglia was proliferated. Amyloid beta(1-40) immunoreactivity was found in a few axons in the white matter after BCAS, whereas Abeta(1-42) was accumulated in the scattered cortical neurons and the axons at ages of 6 months and thereafter in the short- and long-period groups. In the neuropil, both Abeta(1-40) and Abeta(1-42) were deposited in the sham-operated and BCAS-treated mice at ages of 9 and 12 months. There were no differences between the short-period group at ages of 12 months and the long-period group. Filter assay showed an increase of Abeta fibrils in the extracellular enriched fraction. Taken together, chronic cerebral hypoperfusion increased Abeta fibrils and induced Abeta deposition in the intracellular compartment and, therefore, may accelerate the pathological changes of Alzheimer's disease.

Selective impairment of working memory in a mouse model of chronic cerebral hypoperfusion.

BACKGROUND AND PURPOSE: We recently designed a mouse model of chronic cerebral hypoperfusion, in which the cerebral white matter is damaged without significant gray matter lesions. The behavioral characteristics of these mice were studied using a test battery for neurological and cognitive functions. METHODS: Adult C57Bl/6 male mice were subjected to either sham-operation or bilateral common carotid artery stenosis (BCAS) using microcoils with an internal diameter of 0.18 mm. At 30 days after BCAS, 70 animals were divided into 3 groups and subjected to behavioral test batteries. The first group underwent comprehensive behavioral test, including the neurological screen, prepulse inhibition, hot plate, open field, light/dark transition, Porsolt forced swim and contextual and cued fear conditioning (BCAS n=13; sham-operated n=11). The second group was for the working memory task of the 8-arm radial maze test (BCAS n=12; sham-operated n=10), and the third for the reference memory task of the 8-arm radial maze test (BCAS n=13; sham-operated n=11). Another batch of animals were examined for histological changes (BCAS n=11; sham-operated n=12). RESULTS: The white matter including the corpus callosum was consistently found to be rarefied without clear ischemic lesions in the hippocampus. No apparent differences were observed in the comprehensive test batteries between the control and BCAS mice. However, in the working memory tasks tested with the 8-arm radial maze, the BCAS mice made significantly more errors than the control mice (P<0.0001). Again, there were no detectable differences in the reference memory tasks between the groups. CONCLUSIONS: At 30 days after BCAS, working memory deficits as well as white matter changes were apparent in the mice. Working memory deficit was attributable to damage of the frontal-subcortical circuits, suggesting the BCAS model is useful to evaluate the substrates of subcortical vascular dementia.

Loss of cholinergic pathways in vascular dementia of the Binswanger type.

We sought to determine the changes in the cholinergic pathways, which project from the nucleus basalis of Meynert (nBM) and travel in the subinsular region, in vascular dementia of the Binswanger type (VDBT) and Alzheimer's disease (AD). The subinsular regions were examined in 6 autopsied brains with VDBT, 5 brains with AD and 4 control brains without any neurologic diseases. The cholinergic pathway was labeled either by histochemistry for acetylcholine esterase (AChE), a degradatory enzyme of ACh, or by immunohistochemistry for choline acetyltransferase, its synthetic enzyme. The numerical density of nBM neurons did not differ significantly between these groups (163 +/- 49 in the VDBT, 105 +/- 82 in the AD and 198 +/- 76 in the control groups), but with a tendency towards a decrease in the AD group. The subinsular cholinergic fibers were impaired, with relative preservation of the nBM neurons in VDBT, whereas both the subinsular cholinergic fibers and the nBM neurons were degraded in AD. These results indicate that the cholinergic pathway is damaged not only in AD, but also in VDBT, and may further provide a pharmacological basis for treatment with AChE inhibitors in VDBT.