Practical Management for Use of Eculizumab in the Treatment of Severe, Refractory, Non-Thymomatous, AChR + Generalized Myasthenia Gravis: A Systematic Review.

Myasthenia gravis (MG) is a rare autoimmune disorder caused by specific autoantibodies at the neuromuscular junction. MG is classified by the antigen specificity of these antibodies. Acetylcholine receptor (AChR) antibodies are the most common type (74-88%), followed by anti-muscle specific kinase (MuSK) and other antibodies. While all these antibodies lead to neuromuscular transmission failure, the immuno-pathogenic mechanisms are distinct. Complement activation is a primary driver of AChR antibody-positive MG (AChR+ MG) pathogenesis. This leads to the formation of the membrane attack complex and destruction of AChR receptors and the postsynaptic membrane resulting in impaired neurotransmission and muscle weakness characteristic of MG. Broad-based immune-suppressants like corticosteroids are effective in controlling MG; however, their long-term use can be associated with significant adverse effects. Advances in translational research have led to the development of more directed therapeutic agents that are likely to alter the future of MG treatment. Eculizumab is a humanized monoclonal antibody that inhibits the cleavage of complement protein C5 and is approved for use in generalized MG. In this review, we discuss the pathophysiology of MG; the therapeutic efficacy and tolerability of eculizumab, as well as the practical guidelines for its use in MG; future studies exploring the role of eculizumab in different stages and subtypes of MG subtypes; the optimal duration of therapy and its discontinuation; the characterization of non-responder patients; and the use of biomarkers for monitoring therapy are highlighted. Based on the pathophysiologic mechanisms, emerging therapies and new therapeutic targets are also reviewed.

Safety of intravenous immune globulin in an outpatient setting for patients with neuromuscular disease.

INTRODUCTION: Although intravenous immune globulin (IVIg) is used to treat patients in the outpatient setting, there is limited documentation addressing the safety of this practice. METHODS: Retrospective analysis of 438 patients with neuromuscular diseases receiving IVIg in an outpatient setting. RESULTS: Adverse events (AE) overall occurred in 16.9% of patients. Headache was the most common AE, noted in 11.6% of patients. Serious AEs occurred in 0.91% of patients; aseptic meningitis was the only one noted. Multivariate analyses identified the following risk factors for AEs: first-lifetime course of IVIg, higher dose per course of IVIg, diagnosis of myasthenia gravis, women, and younger age. DISCUSSION: Intravenous immune globulin is generally safe to administer in an outpatient setting. Women, myasthenia gravis patients, and those receiving their first course or a higher total dose of IVIg are at an increased risk of experiencing an AE.

Antidepressants modulate intracellular amyloid peptide species in N2a neuroblastoma cells.

It is estimated that 30%-50% of Alzheimer's disease (AD) patients are diagnosed with major or minor depression. Research that addresses the relationship between these two diseases will benefit patients who suffer from depression comorbid with AD and allow further understanding of the neuroanatomy of depression. A clinical study showed that the use of the antidepressant fluoxetin concomitantly with the FDA-approved AD drug rivastigmine provided an improvement in the daily activities and the overall functioning in the patients with cognitive impairment. In an attempt to understand the underlying mechanism for the antidepressant's beneficial effect in AD patients, we evaluated the effects of different classes of antidepressants on the amyloid-ß peptide (Aß) species in N2a neuroblastoma cells overexpressing amyloid-ß protein precursor. The effect of increasing antidepressant concentrations on the intracellular and secreted Aß species is investigated by Western blotting. The tested antidepressants include fluoxetine, paroxetine, maprotiline, and imipramine. Fluoxetine and paroxetine at 10 µM significantly decreased the intracellular level of Aß oligomers and increased the level of Aß monomers. However, imipramine and maprotiline increased the intracellular amount of Aß monomers without affecting Aß oligomers. Based on these results, it is possible that fluoxetine and paroxetine could be beneficial to AD patients via reducing the level of the cytotoxic oligomers and keeping the Aß peptide in the monomeric form. These data could explain some of the beneficial effects of antidepressants in AD patients observed in clinical studies.

Neuroprotective effects and mechanism of cognitive-enhancing choline analogs JWB 1-84-1 and JAY 2-22-33 in neuronal culture and Caenorhabditis elegans.

BACKGROUND: Our previous work indicated that novel analogs of choline have cytoprotective effects in vitro that might be useful in neurodegenerative conditions such as Alzheimer's disease (AD). Furthermore, two lead compounds (JWB1-84-1 and JAY2-22-33) from a library of more than 50 improved cognitive performances in a transgenic mouse model of AD. The purpose of these experiments was to more specifically investigate the neuroprotective capabilities of these lead compounds both in vitro and in vivo. RESULTS: We used N2a cells which express a Swedish mutation in the amyloid precursor protein and presenilin 1 genes to investigate the effect of JWB1-84-1 and JAY2-22-33 on ß-amyloid (Aß) levels and found that both compounds significantly reduced Aß levels. JWB1-84-1 and JAY2-22-33 also protected rat primary cortical neurons from Aß toxicity. Subsequently, we utilized the nematode Caenorhabditis elegans (C. elegans) as an in vivo model organism to identify potential molecular targets of these compounds. In the C. elegans model of Aß toxicity, human Aß is expressed intracellularly in the body wall muscle. The expression and subsequent aggregation of Aß in the muscle leads to progressive paralysis. CONCLUSION: We found that JAY2-22-33 (but not JWB1-84-1) significantly reduced Aß toxicity by delaying paralysis and this protective effect required both the insulin signaling pathway and nicotinic acetylcholine receptors (nAChRs).

Fluoxetine protects against amyloid-beta toxicity, in part via daf-16 mediated cell signaling pathway, in Caenorhabditis elegans.

Alzheimer's disease (AD) is a progressive neurodegenerative disorder and is the most common form of dementia in elderly people. The accumulation of amyloid beta (Abeta) is one of the histopathological hallmarks of AD. Abeta is aggregated to form oligomers which are toxic to neurons and are critical to the onset and progression of AD. In a Caenorhabditis elegans (C. elegans) model of AD, human Abeta is expressed intracellularly in the body wall muscle. The expression and subsequent aggregation of Abeta in the muscle lead to progressive paralysis. Although the mechanism of action is unknown, antidepressants have been used with FDA approved drugs for dementia in AD and have been shown to enhance cognitive function in human and in animal models of AD. We found that the antidepressant fluoxetine, a selective serotonin reuptake inhibitor, significantly delayed Abeta-induced paralysis in the C. elegans model of Abeta toxicity by reducing Abeta oligomers. Our results showed that insulin signaling and DAF-16/FOXO transcription factors were required for fluoxetine-mediated delayed paralysis. We also found that fluoxetine increased thermal stress resistance and extended life span. These findings suggests that fluoxetine may have benefit for the treatment of AD by the reduction of proteotoxicity.

Antidepressants are a rational complementary therapy for the treatment of Alzheimer's disease.

There is a high prevalence rate (30-50%) of Alzheimer's disease (AD) and depression comorbidity. Depression can be a risk factor for the development of AD or it can be developed secondary to the neurodegenerative process. There are numerous documented diagnosis and treatment challenges for the patients who suffer comorbidity between these two diseases. Meta analysis studies have provided evidence for the safety and efficacy of antidepressants in treatment of depression in AD patients. Preclinical and clinical studies show the positive role of chronic administration of selective serotonin reuptake inhibitor (SSRI) antidepressants in hindering the progression of the AD and improving patient performance. A number of clinical studies suggest a beneficial role of combinatorial therapies that pair antidepressants with FDA approved AD drugs. Preclinical studies also demonstrate a favorable effect of natural antidepressants for AD patients. Based on the preclinical studies there are a number of plausible antidepressants effects that may modulate the progression of AD. These effects include an increase in neurogenesis, improvement in learning and memory, elevation in the levels of neurotrophic factors and pCREB and a reduction of amyloid peptide burden. Based on this preclinical and clinical evidence, antidepressants represent a rational complimentary strategy for the treatment of AD patients with depression comorbidity.

Antidepressant stimulation of CDP-diacylglycerol synthesis does not require monoamine reuptake inhibition.

BACKGROUND: Recent studies demonstrate that diverse antidepressant agents increase the cellular production of the nucleolipid CDP-diacylglycerol and its synthetic derivative, phosphatidylinositol, in depression-relevant brain regions. Pharmacological blockade of downstream phosphatidylinositide signaling disrupted the behavioral antidepressant effects in rats. However, the nucleolipid responses were resistant to inhibition by serotonin receptor antagonists, even though antidepressant-facilitated inositol phosphate accumulation was blocked. Could the neurochemical effects be additional to the known effects of the drugs on monoamine transmitter transporters? To examine this question, we tested selected agents in serotonin-depleted brain tissues, in PC12 cells devoid of serotonin transporters, and on the enzymatic activity of brain CDP-diacylglycerol synthase - the enzyme that catalyzes the physiological synthesis of CDP-diacylglycerol. RESULTS: Imipramine, paroxetine, and maprotiline concentration-dependently increased the levels of CDP-diacylglycerol and phosphatidylinositides in PC12 cells. Rat forebrain tissues depleted of serotonin by pretreatment with p-chlorophenylalanine showed responses to imipramine or maprotiline that were comparable to respective responses from saline-injected controls. With fluoxetine, nucleolipid responses in the serotonin-depleted cortex or hippocampus were significantly reduced, but not abolished. Each drug significantly increased the enzymatic activity of CDP-diacylglycerol synthase following incubations with cortical or hippocampal brain tissues. CONCLUSION: Antidepressants probably induce the activity of CDP-diacylglycerol synthase leading to increased production of CDP-diacylglycerol and facilitation of downstream phosphatidylinositol synthesis. Phosphatidylinositol-dependent signaling cascades exert diverse salutary effects in neural cells, including facilitation of BDNF signaling and neurogenesis. Hence, the present findings should strengthen the notion that modulation of brain phosphatidylinositide signaling probably contributes to the molecular mechanism of diverse antidepressant medications.

Anti-depressant natural flavonols modulate BDNF and beta amyloid in neurons and hippocampus of double TgAD mice.

Increasing evidence suggests that depression may be both a cause and consequence of neurological disorders such as Alzheimer's disease (AD), and that anti-depressants could provide an alternative strategy to current AD therapies. Association of side effect and herbal-drug interaction with conventional anti-depressant and St. John's wort warrant investigating new anti-depressant drugs. Anti-depressant effects of ginkgo biloba extract (EGb 761) have been demonstrated in animal models of depression and in human volunteers. We report here that ginkgo flavonols quercetin and kaempferol stimulates depression-related signaling pathways involving brain-derived neurotrophic factor BDNF/phosphorylation of cyclic AMP response element binding protein CREB/postsynaptic density proteins PSD95, and reduces amyloid-beta peptide (Abeta) in neurons isolated from double transgenic AD mouse (TgAPPswe/PS1e9). In addition, enhanced BDNF expression and reduction of Abeta oligomers was confirmed in hippocampus of the double transgenic mice administered with flavonol, which correlates with cognitive improvement behaviors in these mice. The present results suggest that stimulating BDNF and reducing Abeta toxicity by natural flavonols provide a therapeutic implication for treatment of AD.