IV Thrombolysis for central retinal artery occlusion - Real-world experience from a comprehensive stroke center.

OBJECTIVES: Central retinal artery occlusion (CRAO) is a stroke of the retina potentially amenable to intravenous thrombolysis (IVT). We aimed to determine feasibility of an emergency treatment protocol and risk profile of IVT for CRAO in a comprehensive stroke center (CSC). METHODS: We performed a retrospective, observational cohort study including patients with acute CRAO admitted to a CSC over 4 years. Patients are offered IVT if they present with acute vision loss of ≤ 20/200 in the affected eye, have no other cause of vision loss (incorporating a dilated ophthalmologic exam), and meet criteria akin to acute ischemic stroke. We collected socio-demographic data, triage data, time from onset to presentation, IVT candidacy, and rates of symptomatic intracranial hemorrhage (sICH)- or extracranial hemorrhage. RESULTS: 36 patients presented within the study period, mean (standard deviation (SD)) age of 70.7 (10), 52 % female, and median time (Q1, Q3) to ED presentation of 13.5 (4.3, 18.8) h. Patients within 4.5 h from onset presented more commonly directly to our ED (66.6 % vs 37.1 %, p = 0.1). Nine patients (25 %) presented within the 4.5 h window. Of those eligible, 7 (77 %) received IVT. There were no events of intracranial or extracranial hemorrhage. CONCLUSIONS: Our study confirmed that IVT for acute CRAO is feasible. We found a high rate of treatment with IVT of those eligible. However, because 75 % of patients presented outside the treatment window, continued educational efforts are needed to improve rapid triage to emergency departments to facilitate evaluation for possible candidacy with IVT.

Deciphering the Enigma of the Histone H2A.Z-1/H2A.Z-2 Isoforms: Novel Insights and Remaining Questions.

The replication independent (RI) histone H2A.Z is one of the more extensively studied variant members of the core histone H2A family, which consists of many replication dependent (RD) members. The protein has been shown to be indispensable for survival, and involved in multiple roles from DNA damage to chromosome segregation, replication, and transcription. However, its functional involvement in gene expression is controversial. Moreover, the variant in several groups of metazoan organisms consists of two main isoforms (H2A.Z-1 and H2A.Z-2) that differ in a few (3-6) amino acids. They comprise the main topic of this review, starting from the events that led to their identification, what is currently known about them, followed by further experimental, structural, and functional insight into their roles. Despite their structural differences, a direct correlation to their functional variability remains enigmatic. As all of this is being elucidated, it appears that a strong functional involvement of isoform variability may be connected to development.

MeCP2-E1 isoform is a dynamically expressed, weakly DNA-bound protein with different protein and DNA interactions compared to MeCP2-E2.

BACKGROUND: MeCP2-a chromatin-binding protein associated with Rett syndrome-has two main isoforms, MeCP2-E1 and MeCP2-E2, differing in a few N-terminal amino acid residues. Previous studies have shown brain region-specific expression of these isoforms which, in addition to their different cellular localization and differential expression during brain development, suggest that they may also have non-overlapping molecular mechanisms. However, differential functions of MeCP2-E1 and E2 remain largely unexplored. RESULTS: Here, we show that the N-terminal domains (NTD) of MeCP2-E1 and E2 modulate the ability of the methyl-binding domain (MBD) to interact with DNA as well as influencing the turn-over rates, binding dynamics, response to neuronal depolarization, and circadian oscillations of the two isoforms. Our proteomics data indicate that both isoforms exhibit unique interacting protein partners. Moreover, genome-wide analysis using ChIP-seq provide evidence for a shared as well as a specific regulation of different sets of genes. CONCLUSIONS: Our study supports the idea that Rett syndrome might arise from simultaneous impairment of cellular processes involving non-overlapping functions of MECP2 isoforms. For instance, MeCP2-E1 mutations might impact stimuli-dependent chromatin regulation, while MeCP2-E2 mutations could result in aberrant ribosomal expression. Overall, our findings provide insight into the functional complexity of MeCP2 by dissecting differential aspects of its two isoforms.

Fetal alcohol spectrum disorder (FASD) affects the hippocampal levels of histone variant H2A.Z-2.

Fetal alcohol spectrum disorder (FASD) is caused by prenatal exposure to ethanol and has been linked to neurodevelopmental impairments. Alcohol has the potential to alter some of the epigenetic components that play a critical role during development. Previous studies have provided evidence that prenatal exposure to ethanol results in abnormal epigenetic patterns (i.e., hypomethylation) of the genome. The aim of this study was to determine how prenatal exposure to ethanol in rats affects the hippocampal levels of expression of two important brain epigenetic transcriptional regulators involved in synaptic plasticity and memory consolidation: methyl CpG-binding protein 2 (MeCP2) and histone variant H2A.Z. Unexpectedly, under the conditions used in this work we were not able to detect any changes in MeCP2. Interestingly, however, we observed a significant decrease in H2A.Z, accompanied by its chromatin redistribution in both female and male FASD rat pups. Moreover, the data from reverse-transcription qPCR later confirmed that this decrease in H2A.Z is mainly due to down-regulation of its H2A.Z-2 isoform gene expression. Altogether, these data provide strong evidence that prenatal exposure to ethanol alters histone variant H2A.Z during neurogenesis of rat hippocampus.

Factor VIII in Acute Cerebral Ischemia Pilot Study: Biomarker in Patients With Large Vessel Occlusion?

We conducted a prospective serial laboratory cohort study to assess the correlation of factor VIII (FVIII) levels in response to thrombolysis in patients with large vessel occlusion (LVO) and acute ischemic stroke (AIS). Patients with AIS with anterior circulation LVO were eligible for enrollment if treated within 4.5 hours from last seen normal with intravenous tissue plasminogen activator (tPA). Patients (n = 29) had a mean age of 71 years and median National Institute of Health Stroke Scale of 14. Baseline pre-tPA FVIII was not significantly correlated with clot burden score (-0.147, P = .447) or vessel recanalization (-0.133, P = .499). Median FVIII decreased significantly from baseline to 6 hours post-tPA (282% to 161%, P = .002), but delta in FVIII level did not correlate with vessel recanalization (0.013, P = .948). There was no difference between median FVIII level at baseline and 90 days post-AIS. FVIII level decreased significantly after tPA, but baseline FVIII level and early change in FVIII level were not significant predictors of clot burden, vessel recanalization after thrombolysis, or symptomatic hemorrhage.

Right timing in formative program evaluation.

Since many educational researchers and program developers have limited knowledge of formative evaluation, formative data may be underutilized during the development and implementation of an educational program. The purpose of this article is to explain how participatory, responsive, educative, and qualitative approaches to formative evaluation can facilitate a partnership between evaluators and educational researchers and program managers to generate data useful to inform program implementation and improvement. This partnership is critical, we argue, because it enables an awareness of when to take appropriate action to ensure successful educational programs or "kairos". To illustrate, we use examples from our own evaluation work to highlight how formative evaluation may facilitate opportune moments to (1) define the substance and purpose of a program, (2) develop understanding and awareness of the cultural interpretations of program participants, and (3) show the relevance of stakeholder experiences to program goals.

Ischemic stroke after use of the synthetic marijuana "spice".

OBJECTIVES: To report and associate acute cerebral infarctions in 2 young, previously healthy siblings with use of the street drug known as "spice" (a synthetic marijuana product, also known as "K2"), which they independently smoked before experiencing acute embolic-appearing ischemic strokes. METHODS: We present history, physical examination, laboratory data, cerebrovascular imaging, echocardiogram, ECG, and hospital course of these patients. RESULTS: We found that in both siblings spice was obtained from the same source. The drug was found to contain the schedule I synthetic cannabinoid JWH-018. Full stroke workup was unrevealing of a stroke etiology; urine drug screen was positive for marijuana. CONCLUSIONS: We found that our 2 patients who smoked the street drug spice had a temporal association with symptoms of acute cerebral infarction. This association may be confounded by contaminants in the product consumed (i.e., marijuana or an unidentified toxin) or by an unknown genetic mechanism. The imaging of both patients suggests an embolic etiology, which is consistent with reports of serious adverse cardiac events with spice use, including tachyarrhythmias and myocardial infarctions.

Microglial activation is required for Abeta clearance after intracranial injection of lipopolysaccharide in APP transgenic mice.

Inflammation has been argued to play a fundamental role in the pathogenesis of Alzheimer's disease. Mice transgenic for mutant human amyloid precursor protein (APP) develop progressive amyloid deposition, gliosis, and cognitive impairment. Paradoxically, intracranial administration of lipopolysaccharide (LPS) to promote neuroinflammation results in a reduction in amyloid-beta peptide (Abeta) burden concurrent with the inflammatory response. To determine whether microglia mediate Abeta clearance after LPS, we used dexamethasone to inhibit the microglial response. Amyloid precursor protein mice were injected intrahippocampally with either LPS or saline and were allowed to survive for 7 days with or without dexamethasone cotreatment. Brain tissue was then analyzed by immunohistochemistry. Hippocampal Abeta burden was reduced 7 days after LPS injection, and this was prevented by cotreatment with dexamethasone. Markers of microglial activation [CD45, complement receptor 3 (CR3), and macrosialin (CD68)] were increased by LPS, and these increases were attenuated by dexamethasone. Dexamethasone failed to block LPS-induced increases in all microglial markers, and Fcgamma receptors II/III and scavenger receptor A were increased by LPS but were unaffected by dexamethasone cotreatment. These results indicate a complex response by microglia to acute LPS treatment, with only some responses sensitive to steroidal anti-inflammatory drug treatment. Nonetheless, microglial activation was necessary to remove Abeta in this model of neuroinflammation.

Diverse microglial responses after intrahippocampal administration of lipopolysaccharide.

Inflammation has been argued to play a primary role in the pathogenesis of Alzheimer's disease by contributing to the development of neuropathology and clinical symptoms. However, the mechanisms underlying these effects remain obscure. Lipopolysaccharide (LPS) activates the innate immune response and triggers gliosis when injected into the central nervous system. In the studies described in the present work, we evaluated the time course of microgliosis after a single intrahippocampal injection of LPS. Mice were injected bilaterally with 4 mug of LPS. Post-injection survival times were 1, 6, and 24 h, as well as 3, 7, 14, and 28 days. Protein and RNA analyses were performed for inflammatory markers. Significant elevations of cluster differentiation marker CD45, glial fibrillary acidic protein (GFAP), scavenger receptor A (SRA), and Fcgamma receptor mRNA were seen after 24 h. Immunohistochemistry revealed a complex pattern of protein expression by microglia, as well as changes in cell morphologies. RNA and protein for Fcgamma receptor and SRA were transiently elevated, peaked at 3 days, and returned to basal levels after 1 week. In contrast, microglia remained significantly activated through the 28-day time point, as determined by CD45 and complement receptor 3 levels. These findings indicate a multivariate response to LPS, and evaluation of microglial phenotypes may lead to a better understanding of neuroinflammatory diseases.

Dysregulation of Na+/K+ ATPase by amyloid in APP+PS1 transgenic mice.

BACKGROUND: The pathology of Alzheimer's disease (AD) is comprised of extracellular amyloid plaques, intracellular tau tangles, dystrophic neurites and neurodegeneration. The mechanisms by which these various pathological features arise are under intense investigation. Here, expanding upon pilot gene expression studies, we have further analyzed the relationship between Na+/K+ ATPase and amyloid using APP+PS1 transgenic mice, a model that develops amyloid plaques and memory deficits in the absence of tangle formation and neuronal or synaptic loss. RESULTS: We report that in addition to decreased mRNA expression, there was decreased overall Na+/K+ ATPase enzyme activity in the amyloid-containing hippocampi of the APP+PS1 mice (although not in the amyloid-free cerebellum). In addition, dual immunolabeling revealed an absence of Na+/K+ ATPase staining in a zone surrounding congophilic plaques that was occupied by dystrophic neurites. We also demonstrate that cerebral Na+/K+ ATPase activity can be directly inhibited by high concentrations of soluble Abeta. CONCLUSIONS: The data suggest that the reductions in Na+/K+ ATPase activity in Alzheimer tissue may not be purely secondary to neuronal loss, but may results from direct effects of amyloid on this enzyme. This disruption of ion homeostasis and osmotic balance may interfere with normal electrotonic properties of dendrites, blocking intraneuronal signal processing, and contribute to neuritic dystrophia. These results suggest that therapies aimed at enhancing Na+/K+ ATPase activity in AD may improve symptoms and/or delay disease progression.

Passive immunotherapy against Abeta in aged APP-transgenic mice reverses cognitive deficits and depletes parenchymal amyloid deposits in spite of increased vascular amyloid and microhemorrhage.

BACKGROUND: Anti-Abeta immunotherapy in transgenic mice reduces both diffuse and compact amyloid deposits, improves memory function and clears early-stage phospho-tau aggregates. As most Alzheimer disease cases occur well past midlife, the current study examined adoptive transfer of anti-Abeta antibodies to 19- and 23-month old APP-transgenic mice. METHODS: We investigated the effects of weekly anti-Abeta antibody treatment on radial-arm water-maze performance, parenchymal and vascular amyloid loads, and the presence of microhemorrhage in the brain. 19-month-old mice were treated for 1, 2 or 3 months while 23-month-old mice were treated for 5 months. Only the 23-month-old mice were subject to radial-arm water-maze testing. RESULTS: After 3 months of weekly injections, this passive immunization protocol completely reversed learning and memory deficits in these mice, a benefit that was undiminished after 5 months of treatment. Dramatic reductions of diffuse Abeta immunostaining and parenchymal Congophilic amyloid deposits were observed after five months, indicating that even well-established amyloid deposits are susceptible to immunotherapy. However, cerebral amyloid angiopathy increased substantially with immunotherapy, and some deposits were associated with microhemorrhage. Reanalysis of results collected from an earlier time-course study demonstrated that these increases in vascular deposits were dependent on the duration of immunotherapy. CONCLUSIONS: The cognitive benefits of passive immunotherapy persist in spite of the presence of vascular amyloid and small hemorrhages. These data suggest that clinical trials evaluating such treatments will require precautions to minimize potential adverse events associated with microhemorrhage.

Lovastatin modulation of microglial activation via suppression of functional CD40 expression.

Recent studies have shown that the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) possess antiinflammatory and immunomodulatory properties, distinct from their action of lowering serum lipid levels. Moreover, results of epidemiological studies suggest that long-term use of statins is associated with a decreased risk for Alzheimer's disease (AD). Interestingly, lovastatin (one of the most commonly used anticholesterol drugs) treatment of vascular-derived cells has been reported to antagonize activation of the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling pathway, and it is well known that the JAK/STAT pathway plays a central role in interferon-gamma (IFN-gamma)-induced microglial CD40 expression. We and others have previously reported that microglial CD40 expression is significantly induced by IFN-gamma and amyloid-beta (Abeta) peptide. Moreover, it has been shown that CD40 signaling is critically involved in microglia-related immune responses in the CNS. In this study, we examined the putative role of lovastatin in modulation of CD40 expression and its signaling in cultured microglia. RT-PCR, Western immunoblotting, and flow cytometry data show that lovastatin suppresses IFN-gamma-induced CD40 expression. Additionally, lovastatin markedly inhibits IFN-gamma-induced phosphorylation of JAK/STAT1. Furthermore, lovastatin is able to suppress microglial tumor necrosis factor-alpha, interleukin (IL)-beta1 and IL-6 production promoted either by IFN-gamma or by Abeta peptide challenge in the presence of CD40 cross-linking. To characterize further lovastatin's effect on microglial function, we examined microglial phagocytic capability following CD40 cross-linking. Data reveal that lovastatin markedly attenuates CD40-mediated inhibition of microglial phagocytosis of Abeta. These results provide an insight into the mechanism of the beneficial effects of lovastatin in neurodegenerative disorders, particularly Alzheimer's disease.

Passive amyloid immunotherapy clears amyloid and transiently activates microglia in a transgenic mouse model of amyloid deposition.

The role of microglia in the removal of amyloid deposits after systemically administered anti-Abeta antibodies remains unclear. In the current study, we injected Tg2576 APP transgenic mice weekly with an anti-Abeta antibody for 1, 2, or 3 months such that all mice were 22 months at the end of the study. In mice immunized for 3 months, we found an improvement in alternation performance in the Y maze. Histologically, we were able to detect mouse IgG bound to congophilic amyloid deposits in those mice treated with the anti-Abeta antibody but not in those treated with a control antibody. We found that Fcgamma receptor expression on microglia was increased after 1 month of treatment, whereas CD45 was increased after 2 months of treatment. Associated with these microglial changes was a reduction in both diffuse and compact amyloid deposits after 2 months of treatment. Interestingly, the microglia markers were reduced to control levels after 3 months of treatment, whereas amyloid levels remained reduced. Serum Abeta levels and anti-Abeta antibody levels were elevated to similar levels at all three survival times in mice given anti-Abeta injections rather than control antibody injections. These data show that the antibody is able to enter the brain and bind to the amyloid deposits, likely opsonizing the Abeta and resulting in Fcgamma receptor-mediated phagocytosis. Together with our earlier work, our data argue that all proposed mechanisms of anti-Abeta antibody-mediated amyloid removal can be simultaneously active.

Trans polyunsaturated fatty acids have more adverse effects than saturated fatty acids on the concentration and composition of lipoproteins secreted by human hepatoma HepG2 cells.

The objective of this study was to assess the relative long-term effects of linoleic (cis, cis 18:2), linolelaidic (trans, trans 18:2), and palmitic (16:0) acids on hepatic lipoprotein production in HepG2 cells. All fatty acids increased the mass of triglycerides (TG) in the medium and the incorporation of [(3)H]-glycerol into secreted TG; the increase was more pronounced with linoleic acid than with linolelaidic and palmitic acids. The net accumulation in the medium of apolipoprotein (apo) A-I was not affected by the fatty acids tested and moderate changes in that of apoB resulted in apoB/apoA-I mass ratios of 1.05, 1.27 and 0.86 with linoleic, linolelaidic and palmitic acids, respectively. The incorporation of [(14)C]-acetate into cellular plus secreted total sterols was 9.1%, 33.6% and 17.4% of total [(14)C]-labeled lipids with linoleic, linolelaidic and palmitic acids, respectively. Relative to linoleic acid, palmitic acid, and to a greater extent (P < 0.05) linolelaidic acid, increased the secretion and cellular accumulation of [(14)C]-labeled free cholesterol (FC) and cholesteryl esters and decreased those of TG and phospholipids (PL). Compared with linoleic acid, linolelaidic acid increased LDL-cholesterol (C) and HDL-C by 154% (P < 0.001) and 50% (P = 0.016), respectively, whereas palmitic acid increased LDL-C by 17% (P > 0.1) and did not affect HDL-C. The LDL-C to HDL-C ratios were 0.70, 1.18 and 0.96 with linoleic, linolelaidic and palmitic acids, respectively. These differences were not due to altered LDL receptor activity. The PL to C ratios of HDL particles were 1.61, 0.40 and 0.77 with linoleic acid, linolelaidic acid and palmitic acid, respectively. These results suggest that relative to cis polyunsaturated and saturated fatty acids, trans PUFA more adversely affect the concentration and composition of apoA-I- and apoB-containing lipoproteins secreted by HepG2 cells.

A polymorphic gene nested within an intron of the tau gene: implications for Alzheimer's disease.

A previously undescribed gene, Saitohin (STH), has been discovered in the intron between exons 9 and 10 of the human tau gene. STH is an intronless gene that encodes a 128-aa protein with no clear homologs. The tissue expression of STH is similar to tau, a gene that is implicated in many neurodegenerative disorders. In humans, a single nucleotide polymorphism that results in an amino acid change (Q7R) has been identified in STH and was used in a case control study. The Q7R polymorphism appears to be over-represented in the homozygous state in late onset Alzheimer's disease subjects.