An AGS-associated mutation in ADAR1 catalytic domain results in early-onset and MDA5-dependent encephalopathy with IFN pathway activation in the brain.

Background: Aicardi-Goutières syndrome (AGS) is a severe neurodegenerative disease with clinical features of early-onset encephalopathy and progressive loss of intellectual abilities and motor control. Gene mutations in seven protein-coding genes have been found to be associated with AGS. However, the causative role of these mutations in the early-onset neuropathogenesis has not been demonstrated in animal models, and the mechanism of neurodegeneration of AGS remains ambiguous.

Innate immune activation without immune cell infiltration in brains of murine models of Aicardi-Goutières Syndrome.

Chronic inflammation is frequently invoked as a mechanism of neurodegeneration and yet inflammatory cell infiltrates are seldom seen in brains of these disorders. Different disciplines utilize different technologies and methodologies to describe what is immunologically defined as the innate immune response (IIR). We examined murine models of the human neurodegenerative disease Aicardi-Goutières Syndrome, where an IIR is initiated by aberrant RNA metabolism secondary to a mutation in adenosine deaminase acting on RNA gene (ADAR1).

Gamma Knife Radiosurgery in the Management of Hypothalamic Glioma: A Case Report with Long-Term Follow-Up.

Background: Optic pathway/hypothalamic gliomas are rare pediatric brain tumors. The management paradigm for these challenging tumors includes chemotherapy, radiotherapy, or surgical resection, but the optimal management strategy remains elusive. Gamma knife radiosurgery (GKRS) has emerged as a promising treatment for such lesions as documented by a small number of cases in the literature.

Aicardi-Goutières syndrome-associated mutation at ADAR1 gene locus activates innate immune response in mouse brain.

Background: Aicardi-Goutières syndrome (AGS) is a severe infant or juvenile-onset autoimmune disease characterized by inflammatory encephalopathy with an elevated type 1 interferon-stimulated gene (ISG) expression signature in the brain. Mutations in seven different protein-coding genes, all linked to DNA/RNA metabolism or sensing, have been identified in AGS patients, but none of them has been demonstrated to activate the IFN pathway in the brain of an animal. The molecular mechanism of inflammatory encephalopathy in AGS has not been well defined.

Chronic encapsulated expanding hematomas after stereotactic radiosurgery for intracranial arteriovenous malformations.

Objective: Cerebral arteriovenous malformations (AVMs) are rare cerebral vascular lesions that are associated with high morbidity and mortality from hemorrhage; however, stereotactic radiosurgery (SRS) is a well-validated treatment modality. Few reports have delineated a subgroup of patients who develop delayed chronic encapsulated expanding hematomas (CEEHs) despite angiographic evidence of AVM obliteration following radiosurgery. In this report, the authors performed a retrospective review of more than 1000 radiosurgically treated intracranial AVM cases to delineate the incidence and management of this rare entity.

Viral infection and dementia: A brief synthesis.

For the past 400 years, the most common cause of dementia was tertiary syphilis [1]. Its prevalence declined dramatically with the advent of potent antibiotics in the 20 century, but these same antibiotics also helped increase our average lifespan, leading to dramatic increases in the prevalence of age-related dementias. Abundant progress has been made connecting early onset dementias with mutations in neural genes.

Multifocal Necrotizing Leukoencephalopathy With Preferential Microglia Toxicity in a Patient Treated With Chimeric Antigen Receptor T-Cells and Review of the Literature.

Neurotoxic side effects of traditional systemic chemotherapy are abundantly described. The introduction of newly developed biologic therapeutics and cellular immune effector therapies has expanded the spectrum of neurotoxicity. Multifocal necrotizing leukoencephalopathy (MNL) is a pathologic condition of unknown etiology that has been observed in patients after prolonged critical illness.

Emergent Viral Infections of the CNS.

Biological evolution of the microbiome continually drives the emergence of human viral pathogens, a subset of which attack the nervous system. The sheer number of pathogens that have appeared, along with their abundance in the environment, demand our attention. For the most part, our innate and adaptive immune systems have successfully protected us from infection; however, in the past 5 decades, through pathogen mutation and ecosystem disruption, a dozen viruses emerged to cause significant neurologic disease.

Age-Related Pathology Associated with H1N1 A/California/07/2009 Influenza Virus Infection.

Influenza virus infection causes a spectrum of diseases, ranging from mild upper respiratory tract infection to severe lower respiratory tract infection, that can lead to diffuse alveolar damage, interstitial and airspace inflammation, or acute respiratory failure. Mechanisms instructing disease severity are not completely understood, but host, viral, and bacterial factors influence disease outcome. With age being one host factor associated with a higher risk of severe influenza, we investigated regional pulmonary distribution and severity of pneumonia after 2009 H1N1 influenza virus infection in newly weaned, adult, and aged ferrets to better understand age-dependent susceptibility and pathology.

Histologic Appearance of Iatrogenic Obstructive Hydrocephalus in the Fetal Lamb Model.

Introduction: Documentation of histologic findings associated with congenital hydrocephalus in the fetal lamb model is a critical step in evaluating the efficacy of ventriculoamniotic shunting in the human fetus.

Methods: Four fetal sheep had hydrocephalus induced at approximately 95 days' gestation. Two co-twins remained as controls.

A population neuroscience approach to the study of cerebral small vessel disease in midlife and late life: an invited review.

Aging in later life engenders numerous changes to the cerebral microvasculature. Such changes can remain clinically silent but are associated with greater risk for negative health outcomes over time. Knowledge is limited about the pathogenesis, prevention, and treatment of potentially detrimental changes in the cerebral microvasculature that occur with advancing age.

Aged Chinese-origin rhesus macaques infected with SIV develop marked viremia in absence of clinical disease, inflammation or cognitive impairment.

Background: Damage to the central nervous system during HIV infection can lead to variable neurobehavioral dysfunction termed HIV-associated neurocognitive disorders (HAND). There is no clear consensus regarding the neuropathological or cellular basis of HAND. We sought to study the potential contribution of aging to the pathogenesis of HAND.

Persistence of Zika Virus After Birth: Clinical, Virological, Neuroimaging, and Neuropathological Documentation in a 5-Month Infant With Congenital Zika Syndrome.

During the Zika epidemic in Brazil, a baby was born at term with microcephaly and arthrogryposis. The mother had Zika symptoms at 10 weeks of gestation. At 17 weeks, ultrasound showed cerebral malformation and ventriculomegaly.

Human Zika and West Nile virus neurological infections: What is the difference?

The recent epidemic of West Nile Virus (WNV) infection in the United States was associated with severe neurological disease in immunocompromised hosts, while the emergence of Zika virus infection in the Americas has been notable for an association with increased microcephaly in the fetuses of infected mothers. Rare autopsies of WNV infected humans have shown multiple organ involvement with a clear neurotropism. We have recently had the opportunity to examine the distribution of Zika virus in autopsies of newborns from infected pregnancies.

Correction: Zika Virus infection of rhesus macaques leads to viral persistence in multiple tissues.

[This corrects the article DOI: 10.1371/journal.ppat.

The spectrum of neuropathological changes associated with congenital Zika virus infection.

A major concern associated with ZIKV infection is the increased incidence of microcephaly with frequent calcifications in infants born from infected mothers. To date, postmortem analysis of the central nervous system (CNS) in congenital infection is limited to individual reports or small series. We report a comprehensive neuropathological study in ten newborn babies infected with ZIKV during pregnancy, including the spinal cords and dorsal root ganglia (DRG), and also muscle, pituitaries, eye, systemic organs, and placentas.

Zika Virus infection of rhesus macaques leads to viral persistence in multiple tissues.

Zika virus (ZIKV), an emerging flavivirus, has recently spread explosively through the Western hemisphere. In addition to symptoms including fever, rash, arthralgia, and conjunctivitis, ZIKV infection of pregnant women can cause microcephaly and other developmental abnormalities in the fetus. We report herein the results of ZIKV infection of adult rhesus macaques.

Widespread Virus Replication in Alveoli Drives Acute Respiratory Distress Syndrome in Aerosolized H5N1 Influenza Infection of Macaques.

Human infections with highly pathogenic avian influenza A (H5N1) virus are frequently fatal but the mechanisms of disease remain ill-defined. H5N1 infection is associated with intense production of proinflammatory cytokines, but whether this cytokine storm is the main cause of fatality or is a consequence of extensive virus replication that itself drives disease remains controversial. Conventional intratracheal inoculation of a liquid suspension of H5N1 influenza virus in nonhuman primates likely results in efficient clearance of virus within the upper respiratory tract and rarely produces severe disease.

Ultrastructure of Diaschisis Lesions after Traumatic Brain Injury.

We used controlled cortical impact in mice to model human traumatic brain injury (TBI). Local injury was accompanied by distal diaschisis lesions that developed within brain regions anatomically connected to the injured cortex. At 7 days after injury, histochemistry documented broadly distributed lesions, particularly in the contralateral cortex and ipsilateral thalamus and striatum.

Delta inulin-derived adjuvants that elicit Th1 phenotype following vaccination reduces respiratory syncytial virus lung titers without a reduction in lung immunopathology.

Respiratory syncytial virus (RSV) is a significant cause of lower respiratory tract infections resulting in bronchiolitis and even mortality in the elderly and young children/infants. Despite the impact of this virus on human health, no licensed vaccine exists. Unlike many other viral infections, RSV infection or vaccination does not induce durable protective antibodies in humans.

Cerebrospinal Fluid Biomarkers of Simian Immunodeficiency Virus Encephalitis : CSF Biomarkers of SIV Encephalitis.

Antiretroviral therapy has led to increased survival of HIV-infected patients but also increased prevalence of HIV-associated neurocognitive disorders. We previously identified YKL40 as a potential cerebrospinal fluid (CSF) biomarker of lentiviral central nervous system (CNS) disease in HIV-infected patients and in the macaque model of HIV encephalitis. The aim of this study was to define the specificity and sensitivity along with the predictive value of YKL40 as a biomarker of encephalitis and to assess its relationship to CSF viral load.

Emerging Infections of CNS: Avian Influenza A Virus, Rift Valley Fever Virus and Human Parechovirus.

History is replete with emergent pandemic infections that have decimated the human population. Given the shear mass of humans that now crowd the earth, there is every reason to suspect history will repeat itself. We describe three RNA viruses that have recently emerged in the human population to mediate severe neurological disease.