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Toxoplasma gondii & Human Phenotype

Compendium of Known Effects and Ongoing Research

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Toxoplasma gondii infection and schizophrenia: an inter-kingdom communication perspective

October 6, 2016
Elsheikha, H.M., Zhu, X.Q.
Current Opinion in Infectious Diseases 2016; 29: 311-318.
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Purpose of review The apicomplexan protozoan Toxoplasma gondii has a striking predilection for infecting the central nervous system and has been suggested as a risk factor for schizophrenia. Here, we address some of the mechanisms by which T. gondii achieves this by manipulating signaling pathways of the host brain cells. Recent findings Recent years have brought notable progress in the understanding of how the opportunistic parasite T. gondii establishes a successful infection in mammalian brain by secreting effector molecules that manipulate multiple cell functions. Many pathways involved in this inter-kingdom signaling, such as dopaminergic, GABAergic and kynurenine pathways, also have key roles in the development of schizophrenia. More understanding of T. gondii-brain cell interaction holds the key to unlocking the mystery of T. gondii-mediated schizophrenia pathogenesis. Summary T. gondii usurps a variety of host signaling pathways to ensure physiological adaptation, evasion of host immune defense systems, and efficient replication. A detailed knowledge of T. gondii signaling molecules involved in this cross-kingdom communication with host brain cells will probably provide novel means of pharmacologically manipulating host cellular pathways to promote efficient elimination of the parasite and may permit the development of new schizophrenia-modifying therapeutics.

Tagged: acid, behavior, brain, cell-cultures, cognitive impairment, host-pathogen interaction, inter-kingdom signaling, mice, nadph oxidase, Parasite, reproducing increased dopamine, Schizophrenia, Toxoplasma gondii, tyrosine-hydroxylase activity

Mental health

Toxoplasma infection and later development of schizophrenia in mothers

January 5, 2011
Pedersen, M. G., Stevens, H., Pedersen, C. B., Norgaard-Pedersen, B., Mortensen, P. B
American Journal of Psychiatry 2011;168: 814-821
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Objective: Several studies based on clinical samples have found an association between Toxoplasma gondii infection and schizophrenia, and a case-control study among U. S. military personnel with specimens available from both before and after diagnosis found a positive association between T. gondii immunoglobulin G (IgG) antibody level and schizophrenia. These findings have never been replicated in a prospective cohort study. The purpose of this study was to determine whether mothers infected with T. gondii have an elevated risk of schizophrenia or related disorders and whether the risk depends on IgG antibody level. Method: In a register-based prospective cohort study of 45,609 women born in Denmark, the level of T. gondii-specific IgG antibodies was measured in connection with childbirth between 1992 and 1995. Women were followed up from the date of delivery until 2008. Results: A significant positive association between T. gondii IgG antibody level and schizophrenia spectrum disorders was found. Mothers with the highest IgG level had a relative risk of 1.73 (95% confidence interval [CI]=1.12-2.62) compared with mothers with the lowest IgG level. For schizophrenia, the relative risk was 1.68 (95% CI=0.77-3.46). When the mothers were classified according to IgG level, only those with the highest IgG levels had a significantly higher risk of schizophrenia spectrum disorders. Conclusions: Women with high levels of T. gondii-specific IgG antibodies have a significantly elevated risk of developing schizophrenia spectrum disorders.

Tagged: acid, agents, antibodies, brain, disease, gondii infection, molecular mimicry, systém

Mental health

Autism spectrum disorders may be due to cerebral toxoplasmosis associated with chronic neuroinflammation causing persistent hypercytokinemia that resulted in an increased lipid peroxidation, oxidative stress, and depressed metabolism of endogenous and exogenous substances

October 19, 2010
Prandota J.
Research in Autism Spectrum Disorders 2010; 4: 119-155
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Worldwide, approximately 2 billion people are chronically infected with Toxoplasma gondii with largely yet unknown consequences. Patients with autism spectrum disorders (ASD) similarly as mice with chronic toxoplasmosis have persistent neuroinflammation, hypercytokinemia with hypermetabolism associated with enhanced lipid peroxidation, and extreme changes in the weight resulting in obesity or wasting. Data presented in this review suggest that environmental triggering factors such as pregnancy, viral/bacterial infections, vaccinations, medications, and other substances caused reactivation of latent cerebral toxoplasmosis because of changes in intensity of latent central nervous system T. gondii infection/inflammation and finally resulted in development of ASD. Examples of such environmental factors together with their respective biomarker abnormalities are: pregnancy (increased NO, IL-1 beta, TNF-alpha, IL-6, IL-10, prolactin: decreased IFN-gamma, IL-12), neuroborreliosis (increased IL-1 beta, sIL-1R2, TNF-alpha, IFN-gamma, IL-6, IL-10, IL-12, IL-18, transforming growth factor-beta 1 (TGF-beta 1)), vital infections (increased IL-1 beta, IL-6, IL-8, TNF-alpha, IFN-gamma/alpha/beta,TGF-beta 1), thimerosal (increased IL-5, IL-13; decreased IFN-gamma,TNF-alpha,IL-6, IL-12p70, NOS), and valproic acid (increased NO, reactive oxygen species; decreased TNF-alpha, IL-6, IFN-gamma). The imbalances in pro- and antiinflammatory processes could markedly hinder [lost defense mechanisms important for immune control of the parasite, such as the production of NO, cytokines, and reactive oxygen/nitrogen species, tryptophan degradation by indoleamine 2,3-dioxygenase and/or tryptophan 2,3-dioxygenase, limitation of the availability of intracellular iron to T gondii, and the mechanisms mediated by an IFN-gamma responsive gene family. These fluctuations could result in a recurrent profuse multiplication of T. gondii in the brain associated with persistent neuroinflammation, chronic overproduction of pro- and antiinflammatory cytokines, and NO causing increased oxidative stress, and significantly depressed activity of several enzymes including cytochrome P450 monooxygenase family responsible for metabolism of physiological substrates and xenobiotics, such as steroids, fatty acids, prostaglandins, drugs, pollutants, and carcinogens, finally leading to development of ASD. This reasoning may be supported by such abnormal metabolic events as: (1) patients with ASD have significantly decreased melatonin levels caused by marked deficit in acetylserotonin methyltransferase activity, possibly resulting from maternal and/or fetal/postnatal overproduction of NO, characteristic for this clinical entity; (2) thimerosal inhibited both insulin-like growth factor-1- and dopamine-stimulated methylation reactions, and depressed methionine synthase activity, the metabolic events important for promoting normal neurodevelopment; (3) valproic acid, a strong histone deacetylase inhibitor, have potent anti-T. gondii activity. Thus, patients with ASD should be tested for T. gondii infection. (C) 2009 Elsevier Ltd. All rights reserved

Tagged: abnormalities, abnormality, acid, acids, aktivity, autism, autistic spectrum disorders, availability, beta, biomarker, brain, cell-mediated-immunity, central-nervous-system, cerebral, Cerebral toxoplasmosis, change, changes, chronic, chronic neuroinflammation, chronic toxoplasmosis, clinical, congenital cytomegalovirus-infection, consequence, consequences, control, could, cytochrome, cytochrome p450, cytokine, cytokines, data, defense, defense-mechanisms, deficit, degradation, depressed enzyme activities, development, disorder, disorders, drug, drugs, environmental, environmental factors, enzyme, enzymes, event, events, example, families, family, fluctuation, fluctuations, gene, gene families, gene family, gondii, gondii infection, growth, growth-factor-beta, hepatic drug-metabolism, herpes-simplex-virus, histone, histone deacetylase, hypercytokinemia, hypermetabolic state, il-1, il-10, il-12, il-13, il-6, immune, immune irregularities, important, infection, infections, inhibitor, insulin-like, intensity, interferon-inducing agents, intracellular, iron, latent, level, limitation, lipid, lipid-peroxidation, maternal, mechanism, mechanisms, medication, melatonin, metabolism, methionine, methylation, methyltransferase, methyltransferase aktivity, mice, multiplication, nervous, nervous system, neurodevelopment, nf-kappa-b, nitric oxide, nitric-oxide synthase, obesity, or, overproduction, oxidative stress, oxygen, p-450-dependent monooxygenase systems, Parasite, patient, patients, people, persistent, pregnancies, pregnancy, proces, prolactin, prostaglandins, reaction, reactivation, review, species, spectrum, spectrum disorders, spektra, steroids, stress, substrate, systém, t, tgf-beta, tnf-alpha, Toxoplasma, Toxoplasma gondii, toxoplasmosis, tryptophan, tumor-necrosis-factor, vaccination, vital, weight, xenobiotics

Mental health

Topics

  • Behavior 105
  • Cognitive functions 64
  • Mental health 439
  • Morphology 6
  • Motor functions 10
  • Personality 36
  • Physical health 134
  • Reproduction 36
  • Reviews 40
  • Sensory functions 3
  • Uncategorized 2

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Recent articles

  • Mortality Patterns of Toxoplasmosis and Its Comorbidities in Tanzania: A 10-Year Retrospective Hospital-Based Survey February 6, 2020
  • The role of latent toxoplasmosis in the aetiopathogenesis of schizophrenia–the risk factor or an indication of a contact with cat? February 6, 2020
  • The Association between Toxoplasma gondii Infection and Risk of Parkinson’s Disease: A Systematic Review and Meta-Analysis February 6, 2020

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