Acute Motor Axonal Neuropathy Associated with Pandemic H1N1 Influenza A Infection

Background  

Guillain–Barre syndrome (GBS) is a well known entity that has many infectious agents reported as antecedent events. The spectrum of GBS includes acute inflammatory demyelinating polyneuropathy (AIDP), acute motor axonal neuropathy (AMAN), acute motor sensory axonal neuropathy (AMSAN), and some other variants like Miller-Fisher syndrome (MFS).     

Acute Hemorrhagic Leukoencephalopathy Associated with Influenza A (H1N1) Virus

Background

Acute hemorrhagic leukoencephalopathy (AHLE) is a rare condition associated with H1N1. In this condition the infection triggers an autoimmune response which results in perivascular demyelination and hemorrhage in the brain parenchyma.

Methods

We report a case of a patient who developed brain edema and herniation as a result of AHLE.

Results

A 27-year-old presented to a community hospital with fever, dyspnea, and malaise and was found to have H1N1-associated pneumonia. Despite treatment he progressed to acute respiratory distress syndrome and required mechanical ventilation. Due to failure on conventional ventilation, he was transferred to our hospital and was placed on high-frequency oscillatory ventilation. He was showing improvement until day 6 of transfer to our hospital when he was suddenly noted to have a rise in his blood pressure followed by hypotension. The following morning he was noted to have non-reactive pupils and was declared brain dead. Autopsy of the brain was consistent with AHLE.

Conclusions

This case emphasizes the importance of awareness of this disease. The non-specific signs and symptoms, and the use of sedatives, make diagnosis challenging in the early stages of this disease. If suspected early, appropriate imaging can aid in the diagnosis. Treatment with immunosuppressive agents and plasmapheresis may prevent rapid progression and death. This is the first published case of AHLE in association with H1N1 that has been confirmed pathologically.     

The H5N1 Influenza Variant Fujian-Like Hemagglutinin Selected Following Vaccination Exhibits a Compromised Furin Cleavage

The outbreak of H5N1 avian influenza strains infectious to human has dire neurological and pathological consequences. This led to the massive vaccination of host poultry, resulting in a Fujian-like variant (vFJ) resistant to immunization with two mutations at the furin-processing site of hemagglutinin: loss of the P2 Lys and P9 substitution of Gln to Leu within the cleavage site. We synthesized 14mer peptides mimicking the processing site of Fujian-like strains. We found that the peptide with the vFJ sequence is less cleaved as compared to the parent FJ-derived peptide by furin at either neutral or acidic pH values. We hypothesize that the double hemagglutinin mutations in vFJ may result in viruses with less processed hemagglutinin, thereby providing a mechanism for evading immune neutralization.     

Neurologic and Muscular Complications of the 2009 Influenza A (H1N1) Pandemic

In the spring of 2009 a new triple-reassortant of influenza A (H1N1) virus appeared in Mexico and rapidly spread around the world, becoming a pandemic that primarily infected children and uncommonly older adults. Accompanying the pandemic were associated neurologic and muscular syndromes that affected primarily children and included febrile seizures, encephalopathy/encephalitis with or without seizures, delirium, focal neurologic syndromes, Guillain-Barré syndrome, myositis, and myocarditis. Neither the frequency nor the severity of these syndromes appears different from those recognized during periods of infections of previous influenza A viruses. I review the clinical, laboratory, neuroimaging, and pathologic characteristics of the associated syndromes appearing in the first wave of the pandemic, compare them to similar cases occurring in previous years, and explore several theories of pathogenesis.     

H1N1 Encephalitis with Malignant Edema and Review of Neurologic Complications from Influenza

Background  

Influenza virus infection of the respiratory tract is associated with a range of neurologic complications. The emergence of 2009 pandemic influenza A (H1N1) virus has been linked to neurological complications, including encephalopathy and encephalitis.     

Peptide Sharing Between Influenza A H1N1 Hemagglutinin and Human Axon Guidance Proteins

Epidemiologic data suggest that maternal microbial infections may cause fetal neurodevelopmental disorders, potentially increasing susceptibility to heavy psychopathologies such as schizophrenia, schizophreniform disorder, autism, pervasive developmental disorders, bipolar disorders, psychosis, epilepsy, language and speech disorders, and cognitive impairment in adult offspring. However, the molecular pathomechanisms underlying such a relationship are not clear. Here we analyze the potential role of the maternal immune response to viral infection in determining fetal brain injuries that increase the risk of neurological disorders in the adult. We use influenza infection as a disease model and human axon guidance pathway, a key process in the formation of neural network during midgestation, as a potential fetal target of immune insults. Specifically, we examined influenza A H1N1 hemagglutinin (HA), an antigenic viral protein, for amino acid sequence similarity to a random library of 188 axon guidance proteins. We obtain the results that (1) contrary to any theoretical expectations, 45 viral pentapeptide matches are distributed throughout a subset of 36 guidance molecules; (2) in 24 guidance proteins, the peptide sharing with HA antigen involves already experimentally validated influenza HA epitopes; and (3) most of the axon guidance vs HA peptide overlap is conserved among influenza A viral strains and subsets. Taken together, our data indicate that immune cross-reactivity between influenza HA and axon guidance molecules is possible and may well represent a pathologic mechanism capable of determining neurodevelopmental disruption in the fetus.Key words: influenza A H1N1 virus, hemagglutinin, immune cross-reactivity, schizophrenia, autism, bipolar disorder     

Outcome in Patients with H1N1 Influenza and Cerebrovascular Injury Treated with Extracorporeal Membrane Oxygenation

Background  

Although intracranial hemorrhage and infarction have been reported in patients with H1N1 influenza infection treated with extracorporeal membrane oxygenation (ECMO), the clinical outcomes of these patients are not well described.     

Astrocytes Regulate the Expression of Insulin-Like Growth Factor 1 Receptor (IGF1-R) in Primary Cortical Neurons During In Vitro Senescence

The role of insulin-like growth factor 1 (IGF1) pathway as regulator of aging and age-related diseases is increasingly recognized. Recent evidence has been provided that neuronal IGF1-R increases during aging leading to activation of a signaling pathway that causes an increased production of amyloid β-peptide, the principal event in the pathogenesis of Alzheimer’s disease. Here, by using long-term neuronal cultures as a model of aging, we show that astroglial cells are required to upregulate the expression of IGF1-R in neurons during in vitro senescence. Moreover, evidence is provided that the cross-talk between astrocytes and neurons is independent of cell-to-cell contact, and it is mediated by low molecular weight soluble factor(s) released by astrocytes in culture medium. These results suggest that astrocytes could play an important role in aging and age-related pathological processes.     

缺氧/复氧条件下星形胶质细胞水通道蛋白4和5表达变化的研究

目的：观察缺氧/复氧条件下星形胶质细胞水通道蛋白（AQP）4和5表达的变化,探讨脑缺血再灌注后脑水肿与AQP4和AQP5的关系。方法：取新生24h内的SD大鼠皮质新鲜脑组织,进行原代和传代培养。以95%N2和5%CO2造成细胞缺氧,用倒置相差显微镜对细胞进行形态学观察,用锥虫蓝染色法测定缺氧及复氧后不同时间点星形胶质细胞的死亡数以反映星形胶质细胞的存活能力,应用细胞免疫化学技术测定星形胶质细胞缺氧及复氧后各个时间点AQP4、AQP5表达的变化。结果：缺氧4及8h后细胞形态变化不明显,随着复氧时间的延长出现细胞损伤的表现。与对照组比较,缺氧后4及8h有少量细胞死亡（P〈0.05）,随着复氧时间延长细胞死亡数亦逐渐增多（P〈0.01）;缺氧4及8h后,AQP4、AQP5阳性表达细胞数均减少（P〈0.01）,而复氧后AQP4、AQP5阳性表达细胞数逐渐升高并随时间延长呈增高趋势（P〈0.01）。结论：星形胶质细胞对缺氧的耐受能力较强,但复氧时出现明显损伤;AQP4、AQP5表达的变化与缺血-再灌注损伤后脑水肿存在相关性。     

7蛋白酶体抑制剂对星形胶质细胞周期素D1和周期素依赖性激酶4表达的影响

目的：研究蛋白酶体抑制对体外培养的星形胶质细胞周期素Dl（cyclinD1）和周期素依赖性激酶4（CDK4）表达的影响。方法：SD乳鼠皮质星形胶质细胞原代培养,并纯化鉴定;予不同浓度（2和4μmol·L^-1）的蛋白酶体抑制剂（lactacystin）对第二代星形胶质细胞进行短期（12h）急性干预处理,应用免疫荧光及Westernblot检测星形胶质细胞cyclinD1和CDK4表达的水平。结果：纯化传代的皮质星形胶质细胞经胶质纤维酸性蛋白（GFAP）免疫荧光鉴定,其阳性率可达99％;lactacystin2和4μmol·L^-1可诱导星形胶质细胞cyclinDl和CDK4表达的下降,与对照组相比差异有显著统计学意义（P〈0．01）。结论：一定程度蛋白酶体活性抑制可诱导培养的星形胶质细胞cyclinD1和CDK4表达的减少,从而影响胶质细胞细胞周期,促进胶质细胞分化。提示蛋白酶体功能障碍后可能通过影响胶质细胞细胞周期来参与阿尔茨海默病的病理改变。     

Multiple Border-Zone Infarcts Triggered by Influenza A Virus Infection in a Patient With Cerebral Autosomal Dominant Arteriopathy Presenting With Subcortical Infarcts and Leukoencephalopathy

Patients with cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL) can develop multiple border-zone infarcts due to hypotension, hypovolemia, or surgery. We report the case of a 41-year-old woman with CADASIL who developed multiple border-zone infarcts due to influenza A virus infection. The patient had no apparent history or episode of stroke or altered consciousness following the onset of respiratory symptoms, which were due to the influenza A infection. Diffusion-weighted magnetic resonance images of the brain showed multiple acute-phase infarcts in border-zone areas of both cerebral hemispheres and the corpus callosum; fluid-attenuated inversion-recovery magnetic resonance images showed increased signal in the subcortical areas of both temporal poles. Gene analysis identified a heterozygous mutation c.160C>T in exon 2 of the NOTCH3 gene (p.Arg54Cys). A diagnosis of CADASIL was established. Our case demonstrates that infectious conditions such as influenza A can trigger multiple border-zone infarctions in patients with CADASIL.     

Inflammatory effects of highly pathogenic H5N1 influenza virus infection in the CNS of mice

The A/VN/1203/04 strain of the H5N1 influenza virus is capable of infecting the CNS of mice and inducing a number of neurodegenerative pathologies. Here, we examined the effects of H5N1 on several pathological aspects affected in parkinsonism, including loss of the phenotype of dopaminergic neurons located in the substantia nigra pars compacta (SNpc), expression of monoamines and indolamines in brain, alterations in SNpc microglia number and morphology, and expression of cytokines, chemokines, and growth factors. We find that H5N1 induces a transient loss of the dopaminergic phenotype in SNpc and now report that this loss recovers by 90 d after infection. A similar pattern of loss and recovery was seen in monoamine levels of the basal ganglia. The inflammatory response in lung and different regions of the brain known to be targets of the H5N1 virus (brainstem, substantia nigra, striatum, and cortex) were examined at 3, 10, 21, 60, and 90 d after infection. In each of these brain regions, we found a significant increase in the number of activated microglia that lasted at least 90 d. We also quantified expression of IL-1α, IL-1β, IL-2, IL-6, IL-9, IL-10, IL-12(p70), IL-13, TNF-α, IFN-γ, granulocyte-macrophage colony-stimulating factor, granulocyte colony-stimulating factor, macrophage colony-stimulating factor, eotaxin, interferon-inducible protein 10, cytokine-induced neutrophil chemoattractant, monocyte chemotactic protein-1, macrophage inflammatory protein (MIP) 1α, MIP-1β, and VEGF, and found that the pattern and levels of expression are dependent on both brain region and time after infection. We conclude that H5N1 infection in mice induces a long-lasting inflammatory response in brain and may play a contributing factor in the development of pathologies in neurodegenerative disorders.     

Detection of the Cyanotoxins L-BMAA Uptake and Accumulation in Primary Neurons and Astrocytes

We show for the first time that a newly developed polyclonal antibody (pAb) can specifically target the cyanotoxin β-methylamino-L-alanine (BMAA) and can be used to enable direct visualization of BMAA entry and accumulation in primary brain cells. We used this pAb to investigate the effect of acute and chronic accumulation, and toxicity of both BMAA and its natural isomer 2,4-diaminobutyric acid (DAB), separately or in combination, on primary cultures of rat neurons. We further present evidence that co-treatment with BMAA and DAB increased neuronal death, as measured by MAP2 fluorescence level, and appeared to reduce BMAA accumulation. DAB is likely to be acting synergistically with BMAA resulting in higher level of cellular toxicity. We also found that glial cells such as microglia and astrocytes are also able to directly uptake BMAA indicating that additional brain cell types are affected by BMAA-induced toxicity. Therefore, BMAA clearly acts at multiple cellular levels to possibly increase the risk of developing neurodegenerative diseases, including neuro- and gliotoxicity and synergetic exacerbation with other cyanotoxins.     

Narcolepsy and 2009 H1N1 pandemic vaccination in Taiwan

BackgroundSeveral European countries have observed an association between narcolepsy and H1N1 vaccines containing AS03® adjuvant in children/adolescents. In Taiwan, a nationwide campaign starting November 2009 administered H1N1 vaccines without adjuvant or with MF59® adjuvant to 67% of children and 12% of adults.MethodsFor those registered in the 2000–2012 National Health Insurance (NHI) databases, we compared age-stratified (0–4, 5–18, 19–59, and ≥60 years) incidence of first referral for a diagnostic MSLT for the pre-pandemic, pandemic/pre-vaccination, and vaccination/post-pandemic period. We also compared the odds of H1N1 vaccination in each chart-ascertained narcolepsy patient, whoever had an onset of excessive daytime sleepiness between April 2009 and December 2012, with 10 population-based controls from the NHI databases on year of birth, sex, and index date, using conditional logistic regressions.ResultsIncidence of MSLT referral for narcolepsy was highest and significantly increased in the pandemic/pre-vaccination period in the age group 5–18 (IRR 3.40, 95% confidence intervals (CI) 2.12–5.45) and 19–59 (IRR 2.90, 95% CI 1.62–5.02) years. Among 137 confirmed narcolepsy cases (86 adults and 51 children), the odds ratios (ORs) were 1.67 (95% CI 0.81–3.45) (adults) and 1.22 (95% CI 0.62–2.39) (children) for H1N1 vaccination without adjuvant, and 1.39 (95% CI 0.17–11.48) (adults) and 3.66 (95% CI 0.37–36.02) (children) with MF59® adjuvant.ConclusionNo substantial association between the use of H1N1 vaccines and narcolepsy was identified in Taiwan. Instead, the H1N1 infection itself could have played a role in triggering narcolepsy in children and young adults.     

通用腺相关病毒载体构建及表达报告基因GFP的研究

目的　构建基因治疗通用型 AAV载体并检测它转导外源基因作用。方法　使用限制性内切酶切出p SSV9int-质粒中的 AAV病毒 Rep和 Cap基因元件后 ,插入了重组腺病毒专用穿梭质粒 -p ACCMVp L p A的含有CMV启动子、多克隆位点 (MCS)和多聚腺苷酸信号 (Poly A)的表达盒 ,构建了重组 AAV通用载体质粒 p SSHG-CMV。在该质粒 MCS插入 GFP基因后 ,我们使用 p SSHG-CMV-GFP、p GF14 0和 p AAV/Ad 3种质粒共转染 2 93包装细胞 ,制备 GFP重组 AAV,应用斑点杂交实验检测重组病毒滴度度 ,并将该病毒感染新生大鼠星形胶质细胞 ,荧光显微镜观察 GFP表达。结果　重组 AAV的滴度在浓缩前可达 2× 10 11,浓缩后可达 2× 10 13 ,表明成功的构建了重组 AAV载体 ,插入外源基因 GFP后 ,在包装病毒和辅助质粒的联合作用下 ,能产生具有感染性的重组AAV。感染了重组 GFP-AAV的大鼠星形胶质细胞表达了明显的 GFP荧光。结论　本文构建的重组 AAV通用载体 p SSHG-CMV,可转导外源基因 ,用于基因治疗的研究     

单核细胞趋化蛋白-1在大鼠脑缺血再灌注损伤中的表达变化

目的 观察大鼠大脑中动脉闭塞（MCAO）后再灌注不同时间点单核细胞趋化蛋白-1（MCP-1）与基因表达的变化．以探讨其在脑缺血再灌注损伤中的意义。方法 建立大鼠局灶性脑缺血再灌注模型，用免疫荧光双标染色、逆转录-聚合酶链反应（RT-PCR）技术检测MCP-1蛋白表达、mRNA转录水平。结果 （1）缺血再灌注后缺血脑组织中存在表达MCP-1／NSE和MCP-1／GFAP双阳性细胞．提示神经元和神经胶质细胞是产生MCP-1的细胞来源之一。（2）各缺血再灌注组MCP-1 mRNA表达均高于假手术组．再灌注1h MCP-1的mRNA转录即有升高．且随时间延长而进一步升高．24h达到高峰之后逐渐下降。结论 脑缺血再灌注引起MCP-1表达上调．提示MCP-1可能参与了局灶性脑缺血再灌注损伤。