Acute necrotizing encephalopathy.

Influenza virus infection is a rare cause of neurological complications, with acute necrotizing encephalopathy (ANE) being among the deadliest. Due to the low incidence of ANE, literature about its association with influenza B infection is limited. We present the case of a 29-year-old previously healthy man with an imaging and clinical diagnosis of influenza B virus infection and sudden decline in mental status. Magnetic resonance imaging showed multifocal areas of abnormal T2 FLAIR signal and restricted diffusion without significant enhancement, with negative mircobiological studies of cerebrospinal fluid. The patient died despite multiple treatments including an antiviral, steroids, and intravenous immunoglobulin. Due to ANE's more common presentation during childhood, this case report represents one of the few available publications in the adult population.

Increased creativity associated with dopamine agonist therapy: A case report and short review of the literature.

Impulse control disorder (ICD) has been linked to dopamine agonist use in patients with Parkinson's disease. Increased creativity is another cognitive side effect of dopaminergic therapy. While ICD is well recognized in the literature, enhanced creativity as a positive phenomenon is underreported because it does not negatively affect the patients' quality of life. Herein, we report a case of a 49-year-old man with Parkinson's disease who developed enhanced creativity expressed by the acquisition of multiple, new artistic skills with ropinirole treatment. He spent a significant amount of time on painting, carving and axe restoration, selling these artistic products became a source of income. He also reports that these hobbies help him cope with physical limitations caused by Parkinson's disease.

De Novo Myasthenia Gravis Induced by Atezolizumab in a Patient with Urothelial Carcinoma.

The programmed cell death ligand-1 antibody, atezolizumab, is an immune checkpoint inhibitor approved for the treatment of various cancers. Herein, we describe a case of an 87-year-old man with advanced urothelial carcinoma. After surgery, atezolizumab was given. Subsequently, he developed generalized myasthenia gravis (MG) with elevated creatinine kinase and positive anti-striated muscle antibody. Although intravenous immunoglobulin was started, the patient developed cardiac arrhythmia and arrest. Our case not only reported MG as an immune-related adverse event of atezolizumab but also emphasized the significance of the programmed cell death-1 pathway in the pathogenesis of MG.

Aldosterone exerts anti-inflammatory effects on LPS stimulated microglia.

Over the last years, studies on microglia cell function in chronic neuro-inflammation and neuronal necrosis pointed towards an eminent role of these cells in Multiple Sclerosis, Parkinson's and Alzheimer's Disease. It was found, that microglia cell activity can be stimulated towards a pro- or an anti-inflammatory profile, depending on the stimulating signals. Therefore, investigation of receptors expressed by microglia cells and ligands influencing their activation state is of eminent interest. A receptor found to be expressed by microglia cells is the mineralocorticoid receptor. One of its ligands is Aldosterone, a naturally produced steroid hormone of the adrenal cortex, which mainly induces homeostatic and renal effects. We evaluated if the addition of Aldosterone to LPS stimulated microglia cells changes their inflammatory profile. Therefore, we assessed the levels of nitric oxide (NO), iNOS, IL-6, IL-1ß, TNF-α and COX-2 in untreated, LPS-treated and LPS/Aldosterone-treated microglia cells. Furthermore we analyzed p38-MAP-Kinase and NFκB signaling within these cells. Our results indicate that the co-stimulation with Aldosterone leads to a decrease of the LPS-induced pro-inflammatory effect and thus renders Aldosterone an anti-inflammatory agent in our model system.

Anti-inflammatory properties of Honokiol in activated primary microglia and astrocytes.

Honokiol has been used in traditional medicine for the treatment of inflammatory diseases. Activation of glial cells plays an essential role in neurodegenerative disorders. In this study, we show that Honokiol reduces the inflammatory response to LPS of primary cultures of microglia and astrocytes through the inhibition of pro-inflammatory mediators (iNOS, IL-6, IL-1ß and TNF-α) and the simultaneous stimulation of anti-inflammatory cytokines (IL-10). Expression of KLF4 was induced in microglia and astrocytes after treatment with LPS and this response was mitigated by Honokiol. These findings extend our understanding of the anti-inflammatory properties of Honokiol on central glial cells and support its use as a therapeutic compound in neuroinflammatory disorders.

The antidepressant bupropion is a negative allosteric modulator of serotonin type 3A receptors.

The FDA-approved antidepressant and smoking cessation drug bupropion is known to inhibit dopamine and norepinephrine reuptake transporters, as well as nicotinic acetylcholine receptors (nAChRs) which are cation-conducting members of the Cys-loop superfamily of ion channels, and more broadly pentameric ligand-gated ion channels (pLGICs). In the present study, we examined the ability of bupropion and its primary metabolite hydroxybupropion to block the function of cation-selective serotonin type 3A receptors (5-HT3ARs), and further characterized bupropion's pharmacological effects at these receptors. Mouse 5-HT3ARs were heterologously expressed in HEK-293 cells or Xenopus laevis oocytes for equilibrium binding studies. In addition, the latter expression system was utilized for functional studies by employing two-electrode voltage-clamp recordings. Both bupropion and hydroxybupropion inhibited serotonin-gated currents from 5-HT3ARs reversibly and dose-dependently with inhibitory potencies of 87 µM and 112 µM, respectively. Notably, the measured IC50 value for hydroxybupropion is within its therapeutically-relevant concentrations. The blockade by bupropion was largely non-competitive and non-use-dependent. Unlike its modulation at cation-selective pLGICs, bupropion displayed no significant inhibition of the function of anion-selective pLGICs. In summary, our results demonstrate allosteric blockade by bupropion of the 5-HT3AR. Importantly, given the possibility that bupropion's major active metabolite may achieve clinically relevant concentrations in the brain, our novel findings delineate a not yet identified pharmacological principle underlying its antidepressant effect.

Pupil to limbus ratio: Introducing a simple objective measure using two-box method for measuring early anisocoria and progress of pupillary change in the ICU.

INTRODUCTION: Measurement of static pupillary size in the ICU is of importance in cases of acutely expanding intracranial mass lesions. The inaccuracies with subjective assessment of pupillary size by medical personnel preclude its use in emergent neurological situations. OBJECTIVE: To determine if the ratio of pupil to limbus diameter (PLD ratio) measured by a two-box method is a reliable measure of pupil size for detecting early anisocoria and measuring pupillary changes. MATERIALS AND METHODS: The PLD ratio was defined as the ratio of the pupillary diameter measured at a para-horizontal axial plane with the limbus diameter measured at the same or parallel axial plane. A two-box method was used to estimate the diameters of imaged pupils. Eyes were imaged using an iPhone 4S cellphone camera. Background illumination was measured and kept constant. The pupils of a 78-year-old woman, who presented with a large intra-axial parenchymal hemorrhage, were imaged. The patient had left pupillary miosis in dark but not in bright light. After presenting this case along with the images of the pupillary examination, a group of 21 medical staff were asked several questions on the pupillary examination. Reliability of PLD ratio were assessed via standard error of mean (S.E.M) of PLD ratios for 3 different subjects each imaged under constant illumination and fixation but from different angles to the optical axis. RESULTS: Analysis of questionnaire data together with PLD ratios revealed that ~ 14% and 10% of participants could estimate the pupillary size in darkness and bright light respectively but none were simultaneously accurate indicating that subjective assessment of pupillary size was unreliable. The approach towards a systematic pupillary examination was inconsistent among the participants. The PLD ratio was found to be a reliable measure of pupillary size with standard error of mean below 0.1 mm for the three subjects tested. CONCLUSION: Static pupillary sizes can be objectively and consistently evaluated using PLD ratios using a two-box method. PLD ratios are resistant, within limits, to changes in imaging angle or choice of para-horizontal axes for measurement.

Is initial preservation of deep tendon reflexes in West Nile Virus paralysis a good prognostic sign?

Typical West Nile virus paralysis is characterized by muscle weakness, decreased tone, and loss of deep tendon reflexes attributed to destruction of anterior horn cells. Two cases in which deep tendon reflexes were initially preserved in the presence of profound and persistent muscle weakness are presented here. In both cases, deep tendon reflexes were later severely attenuated or lost, while weakness of the involved muscles remained profound and unchanged. Both patients showed good motor recovery at 6 months. Initial preservation of deep tendon reflexes in the presence of persistent muscle weakness indicates that in the early stages of disease, the muscle weakness in these two cases was not caused by destruction of anterior horn cells. Pathology involving anterior horns preceding AHC destruction could potentially disrupt upper motor neuron pathways to anterior horn cells, causing weakness with initial preserved deep tendon reflexes.

Pathophysiological processes in multiple sclerosis: focus on nuclear factor erythroid-2-related factor 2 and emerging pathways.

Multiple sclerosis (MS) is a disease of the central nervous system that is characterized by the demyelination of neuronal axons. Four different patterns of demyelination have been described, showing the heterogeneity in the immunopathologic processes involved in the demyelination. This review will focus on reactive oxygen species (ROS)-related inflammation in MS. Special emphasis will be placed on the nuclear factor erythroid-2-related factor 2 (Nrf2) as it regulates the transcription of ROS-protective genes. In the cytosol, Nrf2 binds to Keap1 (Kelch-like ECH-associated protein 1), and together they are degraded by the 26S proteasome after ubiquitination. If challenged by ROS Nrf2, binding to Keap1 is abrogated, and it translocates into the nucleus. Here it binds to the antioxidant response element and to a small protein termed Maf (musculoaponeurotic fibrosarcoma oncogene homolog). This leads to an enhanced transcription of ROS protective genes and represents the physiological answer against ROS challenge. It has been shown that dimethyl fumarate (DMF) has the same effect and leads to an enhanced transcription of ROS-protective genes. This response is mediated through a reduced binding of Nrf2 to Keap1, thus resulting in a higher level of free Nrf2 in the cytosol. Consequently, more Nrf2 translocates to the nucleus, promoting transcription of its target genes. DMF has been used for the treatment of psoriasis for many years in Germany without the occurrence of major side effects. In psoriasis, DMF reduces ROS-related inflammation in skin. A DMF analog, BG-12, was recently approved for the treatment of relapsing-remitting MS by the European Union and the US Food and Drug Administration. As an oral formulation, it gives patients a convenient and effective alternative to the injectable immune modulators in the long-term treatment of MS.

Glial Cell Line-Derived Neurotrophic Factor Family Members Reduce Microglial Activation via Inhibiting p38MAPKs-Mediated Inflammatory Responses.

Previous studies have shown that glial cell line-derived neurotrophic factor (GDNF) family ligands (GFL) are potent survival factors for dopaminergic neurons and motoneurons with therapeutic potential for Parkinson's disease. However, little is known about direct influences of the GFL on microglia function, which are known to express part of the GDNF receptor system. Using RT-PCR and immunohistochemistrym we investigated the expression of the GDNF family receptor alpha 1 (GFR alpha) and the coreceptor transmembrane receptor tyrosine kinase (RET) in rat microglia in vitro as well as the effect of GFL on the expression of proinflammatory molecules in LPS activated microglia. We could show that GFL are able to regulate microglia functions and suggest that part of the well known neuroprotective action may be related to the suppression of microglial activation. We further elucidated the functional significance and pathophysiological implications of these findings and demonstrate that microglia are target cells of members of the GFL (GDNF and the structurally related neurotrophic factors neurturin (NRTN), artemin (ARTN), and persephin (PSPN)).

Dimethylfumarate inhibits microglial and astrocytic inflammation by suppressing the synthesis of nitric oxide, IL-1beta, TNF-alpha and IL-6 in an in-vitro model of brain inflammation.

BACKGROUND: Brain inflammation plays a central role in multiple sclerosis (MS). Dimethylfumarate (DMF), the main ingredient of an oral formulation of fumaric acid esters with proven therapeutic efficacy in psoriasis, has recently been found to ameliorate the course of relapsing-remitting MS. Glial cells are the effector cells of neuroinflammation; however, little is known of the effect of DMF on microglia and astrocytes. The purpose of this study was to use an established in vitro model of brain inflammation to determine if DMF modulates the release of neurotoxic molecules from microglia and astrocytes, thus inhibiting glial inflammation. METHODS: Primary microglial and astrocytic cell cultures were prepared from cerebral cortices of neonatal rats. The control cells were treated with LPS, an accepted inducer of pro-inflammatory properties in glial cells, and the experimental groups with LPS and DMF in different concentrations. After stimulation/incubation, the generation of nitric oxide (NO) in the cell culture supernatants was determined by measuring nitrite accumulation in the medium using Griess reagent. After 6 hours of treatment RT-PCR was used to determine transcription levels of iNOS, IL-1beta, IL-6 and TNF-alpha mRNA in microglial and astrocytic cell cultures initially treated with DMF, followed after 30 min by LPS treatment. Moreover, we investigated possible involvement of the ERK and Nrf-2 transduction pathway in microglia using western blot analysis. RESULTS: Pretreatment with DMF decreased synthesis of the proinflammatory mediators iNOS, TNF-alpha, IL-1beta and IL-6 at the RNA level in activated microglia and astrocytes in vitro, associated with a decrease in ERK phosphorylation in microglia. CONCLUSIONS: Collectively, these results suggest that the neuroprotective effects of DMF may be in part functionally attributable to the compound's ability to inhibit expression of multiple neuroinflammatory mediators in brain of MS patients.

Regulation of activin A synthesis in microglial cells: pathophysiological implications for bacterial meningitis.

Previous studies have shown that activin A, a neuroprotective cytokine and dimeric polypeptide composed of two betaA subunits, is elevated in the cerebrospinal fluid of patients suffering from bacterial meningitis. In this study, to elucidate further the functional significance and pathophysiological implications of these findings, we demonstrated that microglial cells are not only the source but also the target cells of activin A in the central nervous system: immunohistochemistry and RT-PCR revealed expression of activin subunit betaA mRNA as well as activin receptor type I and type II mRNA in rat microglia in vitro. Further studies showed that activin enhances microglial proliferation and decreases the gamma-interferon-induced synthesis of nitric oxide, one of several microglial mediators involved in the inflammatory response in microglia activation. Furthermore, quantitative RT-PCR, Western blotting, and ELISA showed an inhibitory effect of activin on inducible nitric oxide synthase, tumor necrosis factor-alpha, interleukin-6, and interleukin-1beta gene and protein levels after lipopolysaccharide treatment. We suggest that the increased synthesis of activin A is directly involved, via influence on microglia cell functions, in the modulation of the inflammatory response in bacterial meningitis.

Expression and regulation of antimicrobial peptide rCRAMP after bacterial infection in primary rat meningeal cells.

Bacterial meningitis is characterized by an inflammation of the meninges and continues to be an important cause of mortality and morbidity. Meningeal cells cover the cerebral surface and are involved in the first interaction between pathogens and the brain. Little is known about the role of meningeal cells and the expression of antimicrobial peptides in the innate immune system. In this study we characterized the expression, secretion and bactericidal properties of rat cathelin-related antimicrobial peptide (rCRAMP), a homologue of the human LL-37, in rat meningeal cells after incubation with different bacterial supernatants and the bacterial cell wall components lipopolysaccharide (LPS) and peptidoglycan (PGN). Using an agar diffusion test, we observed that supernatants from meningeal cells incubated with bacterial supernatants, LPS and PGN showed signs of antimicrobial activity. The inhibition of rCRAMP expression using siRNA reduced the antimicrobial activity of the cell culture supernatants. The expression of rCRAMP in rat meningeal cells involved various signal transduction pathways and was induced by the inflammatory cytokines interleukin-1, -6 and tumor necrosis factor alpha. In an experimental model of meningitis, infant rats were intracisternally infected with Streptococcus pneumoniae and rCRAMP was localized in meningeal cells using immunohistochemistry. These results suggest that cathelicidins produced by meningeal cells play an important part in the innate immune response against pathogens in CNS bacterial infections.

Erythropoietin does not attenuate cytokine production and inflammation in microglia--implications for the neuroprotective effect of erythropoietin in neurological diseases.

Erythropoietin is a hematopoietic cytokine which is also produced in the brain under hypoxia. Since this pathology is associated with glial cell activation and release of cytotoxic molecules, we investigated the expression of EPO receptors (EPO-R) and effects of erythropoietin on microglial cell functions in vitro using RT-PCR, Western immunoblotting, nitric oxide measurement, tumor necrosis factor-alpha-(TNF-alpha)-ELISA and gel shift assay analyses. Furthermore, we examined if erythropoietin could modulate proliferation of microglia. As shown by reverse transcription-polymerase chain reaction and immunocytochemistry, rat microglial cells and the murine microglia cell line BV-2 express the EPO-R. However, EPO showed no effect on the release of the proinflammatory mediators' nitric oxide and TNF-alpha. Moreover, EPO was not able to reduce the LPS (lipopolysaccharide) stimulated translocation of the proinflammatory transcription factor NF-kappaB into the nucleus of murine microglia, but induced (3)H-thymidine incorporation into DNA of microglial cells. These results show that microglia are target cells for erythropoietin which possesses mitogenic, but not anti-inflammatory effects on microglia. Therefore, the well-documented neuroprotective effects of erythropoietin could not be ascribed to an anti-inflammatory effect on microglia.

Role of glial cells in the functional expression of LL-37/rat cathelin-related antimicrobial peptide in meningitis.

Antimicrobial peptides are intrinsic to the innate immune system in many organ systems, but little is known about their expression in the central nervous system. We examined cerebrospinal fluid (CSF) and serum from patients with active bacterial meningitis to assess antimicrobial peptides and possible bactericidal properties of the CSF. We found antimicrobial peptides (human cathelicidin LL-37) in the CSF of patients with bacterial meningitis but not in control CSF. We next characterized the expression, secretion, and bactericidal properties of rat cathelin-related antimicrobial peptide, the homologue of the human LL-37, in rat astrocytes and microglia after incubation with different bacterial components. Using real-time polymerase chain reaction and Western blotting, we determined that supernatants from both astrocytes and microglia incubated with bacterial component supernatants had antimicrobial activity. The expression of rat cathelin-related antimicrobial peptide in rat glial cells involved different signal transduction pathways and was induced by the inflammatory cytokines interleukin 1beta and tumor necrosis factor. In an experimental model of meningitis, infant rats were intracisternally infected with Streptococcus pneumoniae, and rat cathelin-related antimicrobial peptide was localized in glia, choroid plexus, and ependymal cells by immunohistochemistry. Together, these results suggest that cathelicidins produced by glia and other cells play an important part in the innate immune response against pathogens in central nervous system bacterial infections.

Human neuromelanin induces neuroinflammation and neurodegeneration in the rat substantia nigra: implications for Parkinson's disease.

Parkinson's disease (PD) is a common neurodegenerative disorder characterized by a selective loss of dopaminergic neurons in the substantia nigra (SN). It has been suggested that microglial inflammation augments the progression of PD. Neuromelanin (NM), a complex polymer pigment found in catecholaminergic neurons, has sparked interest because of the suggestion that NM is involved in cell death in Parkinson's disease, possibly via microglia activation. To further investigate the possible role of NM in the pathogenesis of PD, we conducted in vivo experiments to find out whether microglial cells become activated after injection of human neuromelanin (NM) into (1) the cerebral cortex or (2) the substantia nigra to monitor in this PD-relevant model both microglial activation and possible neurodegeneration. In this study, adult male Wistar rats received an intracerebral injection of either NM, bacterial lipopolysaccharide (LPS, positive control), phosphate-buffered saline (PBS, negative control) or colloidal gold suspension (negative particular control). After different survival times (1, 8 or 12 weeks), brain slices from the cerebral cortex or substantia nigra (SN, 1 week) were stained with Iba-1 and/or GFAP antibody to monitor microglial and astrocytic reaction, and with tyrosine hydroxylase (TH) to monitor dopaminergic cell survival (SN group only). The injection of LPS induced a strong inflammatory response in the cortex as well in the substantia nigra. Similar results could be obtained after NM injection, while the injection of PBS or gold suspension showed only moderate or no glial activation. However, the inflammatory response declined during the time course. In the SN group, there was, apart from strong microglia activation, a significant dopaminergic cell loss after 1 week of survival time. Our findings clearly indicate that extracellular NM could be one of the key molecules leading to microglial activation and neuronal cell death in the substantia nigra. This may be highly relevant to the elucidation of therapeutic strategies in PD.

Neuroprotection with angiotensin receptor antagonists: a review of the evidence and potential mechanisms.

The peptide hormone angiotensin (A)-II, the major effector peptide of the renin-angiotensin system (RAS), is well established to play a pivotal role in the systemic regulation of blood pressure, fluid, and electrolyte homeostasis. Recent biochemical and neurophysiologic studies have documented local intrinsic angiotensin-generating systems in organs and tissues such as the brain, retina, bone marrow, liver, and pancreas. The locally generated angiotensin peptides have multiple and novel actions including stimulating cell growth and anti-proliferative and/or antiapoptotic actions. In the mammalian brain, all components of the RAS are present including angiotensin receptor subtypes 1 (AT(1)) and 2 (AT(2)). A-II exerts most of its well defined physiologic and pathophysiologic actions, including those on the central and peripheral nervous system, through its AT(1) receptor subtype. While the AT(1) receptor is responsible for the classical effects of A-II, it has been found that the AT(2) receptor is linked to totally different signalling mechanisms and this has revealed hitherto unknown functions of A-II. AT(2) receptors are expressed at low density in many healthy adult tissues, but are upregulated in a variety of human diseases. This receptor not only contributes to stroke-related pathologic mechanisms (e.g. hypertension, atherothrombosis, and cardiac hypertrophy) but may also be involved in post-ischemic damage to the brain. It has been reported that the AT(2) receptor regulates several functions of nerve cells, e.g. ionic fluxes, cell differentiation, and neuronal tissue regeneration, and also modulates programmed cell death. In this article, we review the experimental evidence supporting the notion that blockade of brain AT(1) receptors can be beneficial with respect to stroke incidence and outcome. We further delineate how AT(2) receptors could be involved in neuronal regeneration following brain injury such as stroke or CNS trauma. The current review is focussed on some of the new functions arising from the locally formed A-II with particular attention to its emerging neuroprotective role in the brain.

The neuromelanin of human substantia nigra: physiological and pathogenic aspects.

Neuromelanin (NM) accumulates as a function of age in normal human substantia nigra (SN) but is relatively depleted in the SN of patients with Parkinson disease (PD). Several studies have been performed to further our understanding of the role of NM in neuronal aging and neurodegenerative mechanisms of PD. To this purpose, NM from human SN was isolated and its structure and molecular interactions were investigated. Cysteinyl-dopamine was shown to be one precursor of NM synthesis. A striking affinity of NM for specific metals, lipids, drugs and pesticides was found in vitro, and in animal and human brain postmortem studies. Because of these affinities, NM seems to play a protective role in the human brain by blocking toxic molecules. On the other hand, experiments in cell culture indicate that NM can activate microglia, eliciting the release of cytotoxic factors that can induce neurodegeneration.

Neuromelanin of the substantia nigra: a neuronal black hole with protective and toxic characteristics.

Neuromelanin accumulates in dopaminergic neurons during normal aging, and in Parkinson's disease, neurons with this pigment are those that selectively degenerate. Intraneuronal neuromelanin could play a protective role during its synthesis by preventing the toxic accumulation of cytosolic catechol derivatives and, in addition, by its ability to scavenge reactive metals, pesticides and other toxins to form stable adducts. However, dying neurons in Parkinson's disease that release neuromelanin might induce a vicious cycle of chronic neuroinflammation and neuronal loss.