مقالات پذیرفته شده در هفتمین کنگره بین المللی زیست پزشکی
Parasite and brain disorder: effects of Toxoplasma on Schizophrenia
Parasite and brain disorder: effects of Toxoplasma on Schizophrenia
Mohammad Amoozadeh,1,*Maryam Jafari,2Nazanin Kazemian,3
1. Student research committee, Anzali International Medical Campus, Guilan University of Medical Sciences, Guilan,Iran 2. Student research committee, Anzali International Medical Campus, Guilan University of Medical Sciences, Guilan,Iran 3. Student research committee, Anzali International Medical Campus, Guilan University of Medical Sciences, Guilan,Iran
Introduction: Many scientific evidence points show the central role of the immune system in the etiopathogenesis of Schizophrenia and some related psychiatric disorders. Some factors among genetics, neuropathological, neuroimaging, and metabolic involve the immune system. Many studies indicate some degree of immune dysregulation and inflammation in the brain of individuals with Schizophrenia. Some organisms can stay in the non-replicating phase or very slow replication, called the latent phase, and cause inflammation in the brain or other organs. Finally, genetic factors are strongly associated with Schizophrenia. Thus, infection organisms that interact with host genetic factors are likely to play a central role in Schizophrenia. Although many pathogenic agents meet these criteria, the one that has been studied the most is the apicomplexan protozoan Toxoplasma gondii. Toxoplasma is classified as a pervasive pathogen and infects nearly a billion people in the world. Initial infection with Toxoplasma is associated with a few symptoms that may not be identified. It also induces lifelong cyst formation mostly in the brain and other organs like the retina and muscles. This research aims to gain a correct understanding of the relationship between Toxoplasma and Schizophrenia. By using it we can treat or induce the symptoms of Schizophrenia with the medicine that is used to cure Toxoplasma.
Methods: The present review was conducted through the electrical scientific databases including Google Scholar, and PubMed by searching with keywords including Toxoplasma, and Schizophrenia. After these articles were reviewed, a general conclusion was extracted from all the articles.
Results: The results show that children of mothers with a virulent strain of Toxoplasma infection were at higher risk of developing psychiatric disorders compared to uninfected control mothers. As noted before, most of the Toxoplasma cysts are located in the brain, so these are not accessible. To overcome this limitation there is a non-invasive, highly sensitive, and specific method for the measurement of cysts and recognition of the latent phase, and it’s called MAG1. There is a relationship between behavior changes with the number of cysts and the MAG1-positive patients, As the number of cysts and MAG1 increases, behavioral changes are more obvious. Behavioral changes include predator odor aversion and anxiety-related behavior. In one of the experiments conducted on mice, it was found that mice with a high level of MAG1(MAG1>0.5) exhibited reduced locomotor and exploratory activity, impaired object recognition memory, and lack of response to amphetamine-induced activity. These changes were not found in mice with lower levels of cyst burden(MAG1<0.5). Some changes include altered fiber density, loss of fiber continuity, reduction of synaptic protein PSD95, and synaptophysin. Gray matter volume also decreases in Toxoplasma-positive patients.
Conclusion: Many studies linked Toxoplasma to psychiatric disorders including schizophrenia. The multifaceted effects of Toxoplasma infection on neuroinflammation, neurodegeneration, and behavior are only beginning to be understood. Toxoplasma as a neurotropic pathogen may affect information processing in a wide variety of functional brain systems. Although much data points to the role of Toxoplasma infections in the pathogenesis of schizophrenia, the final documentation of this connection shows that anti-Toxoplasma drugs moderate the clinical symptoms or course of psychiatric disorders. Toxoplasma infection can open a door to understanding the complexity of human neurological disease.