Presentation Abstract

Session: Poster I
Monday, Dec 06, 2010, 5:30 PM - 7:30 PM
Presentation: 128 - Latent Toxoplasmosis Reduces Gray Matter Density in Schizophrenia but not in Controls. Voxel-Based-Morphometry (VBM) Study.
Location: Sparkle Ballroom, Poster Board: 128
Pres. Time: Monday, Dec 06, 2010, 5:30 PM - 7:30 PM
Author(s): Jiri Horacek, Jaroslav Flegr, Jaroslav Tintera, Tomas Novak, Martin Brunovsky, Vera Bubenikova-Valesova, Tomas Palenicek, Cyril Höschl. Prague Psychiatric Centre, Prague, Czech Republic
Abstract: Background: The role of coccidian protozoa Toxoplasma gondii represents one of the most enigmatic and unexplained questions in the field of pathophysiology of schizophrenia. Epidemiological studies suggest that latent toxoplasmosis is associated with a substantially higher risk of schizophrenia but a causal relationship has not been established as yet. To address the role of latent Toxoplasma gondii (T. gondii) infection in pathophysiology of schizophrenia we studied the influence of latent toxoplasmosis on brain morphology in schizophrenia.

Methods: Magnetic resonance imaging was analyzed by an optimized voxel-based-morphometry (VBM) in 44 schizophrenic patients (12 T. gondii positive) and 56 controls (13 T. gondii positive). The full factorial model of analysis of variance with diagnosis and seropositivity for latent toxoplasmosis as factors was used to address the differences in gray and white matter. For all VBM analyses, total brain volume (TBV) was used as a nuisance covariate.

Results: VBM analyses showed the grey matter (GM) volume reduction in schizophrenia patients compared with controls bilaterally in the neocortical regions, hippocampus, middle and posterior cingulate and in the caudate. In the subgroup of patients and controls seropositive to T. gondii the reduction of GM was located in the same regions as in the whole sample and consisted of 11660 over-threshold voxels (p=0.05, FWR corrected). The differences between T. gondii negative patients and controls consisted only of 289 voxels in temporal and mediotemporal regions. T. gondii seropositivity as a factor had no influence on brain volumes in controls but was strongly associated with GM reduction in patients.

Discussion: Our study is the first to document that latent toxoplasmosis reduces GM in schizophrenia but not in controls. The higher morphological vulnerability of patients but not controls to T. gondii infection represents an indirect support for the epidemiological evidence of the role of latent toxoplasmosis in schizophrenia. T. gondii can affect gray matter by several mechanisms including kynurenine metabolites and dopamine overactivity.
Acknowledgments: This work was supported by grants 1M0517 and VZ 0021620816 and 0021620828 from the MSMT CR.
Disclosures:  J. Horacek: None. J. Flegr: None. J. Tintera: None. T. Novak: None. M. Brunovsky: None. V. Bubenikova-Valesova: None. T. Palenicek: None. C. Höschl: None.

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