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Catechol o methyltransferase gene expression in

Gene, Schizophrenia, Stress


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As Schizophrenia (SCZ) is the outcome of gene-gene-environmental interactions, you will find possibly different pathophysiological components in different SCZ subtypes based on the risk factors. This research was was executed to examine the impacts of one of the most likely interactions, we. e. “dopamine and stress”, in SCZ pathogenesis. In this article, we looked at the connection between “War Trauma”, devoid of brain shock, and Catechol-O-Methyltransferase (COMT) gene expression. Employing real-time PCR analysis we all measured COMT gene expression level inside the blood cells of 66 subjects in four groups, namely expert SCZ sufferers as “stress-exposed SCZ” (S-SCZ), their healthy and balanced brothers since “their genetically closest relatives” (S-Siblings), SCZ patients without any history of significant stress while “Non-stress-exposed SCZ” (NoS-SCZ), as well as the control group. The COMT gene expression was distinct between the S-SCZ and NoS-SCZ groups, but not at statistically significant level, However , the COMT appearance level was significantly lowered in 3 groups of S-SCZ, their healthful siblings, and NoS-SCZ teams compared to the control group. This kind of data facilitates that the reduced blood COMT expression which can be associated with larger dopamine level is involved both in stress-induced and non-stress induced SCZ.


Gene appearance, Environment, Dopamine, War stress, Blood.


  • Catechol-O-Methyltransferase (COMT) gene phrase was downregulated in stress-induced and non-stress induced schizophrenia (SCZ) patients.
  • COMT has a key role in different subtypes of SCZ.
  • COMT gene expression was significantly downregulated in stress-exposed SCZ and the healthy friends.
  • COMT might provides a role in stress susceptibility specially inside the development of stress-induced SCZ.


Schizophrenia (SCZ) is a sophisticated mental disorder that affects 0. five per cent to 1% of standard population (Owen et ‘s., 2016, Sadock and Ruiz, 2015, Simeone et ‘s., 2015). Each year, almost you to 1. five individuals every 10, 000 are affected by this kind of major mental disorder (Owen et approach., 2016). SCZ is the third cause of impairment, has imposed a large financial load on the western neighborhoods (Sadock and Ruiz, 2015), and it is more prevalent in expanding countries (Brown, 2011).

SCZ encompasses a large number of environmental risk elements, such as mother’s toxins and radiation exposure, maternal weakness, maternal illness, maternal pressure, paternal age (above forty years), mother’s obstetrics and delivery issues, birth time, social being rejected, immigration, difficulty, drug abuse, and growth in densely inhabited or cities (Janoutova ain al., 2016, Owen et al., 2016). In general, responsibility to SCZ is predicted to be impacted by environmental risk factors by 11% (Sullivan et al., 2003) to approximately fifty percent (Uher and Zwicker, 2017). On the other hand, in some studies, the involvement of hereditary elements in the progress SCZ has become reported to get from 60 per cent to 80% (Cardno and Gottesman, 2000, Purcell ou al., 2009), However , these kinds of risk percentages have been reported to be small in other research (van Os and Scam, 2003, Zuk et al., 2012). Innate research has located more than 90 chromosomal loci (Schizophrenia Working Group of the Psychiatric Genomics, 2014) and 2000 genetics to be related to the disorder, but each one has a little effect size (Petronis, 2004). Overall, cumulative effects of genetic and environmental risk elements have been traced in the SCZ pathogenesis (Petronis, 2004).

Psychological tension is considered while the main actual element in the majority of the environmental risk factors. It is often shown that ordinary causes have more severe negative emotional effects upon SCZ individuals (Van Winkel et al., 2008b). In fact , there are many prevalent genetic and environmental risk factors which usually dysregulate hypothalamic”pituitary”adrenal (HPA) axis and have roles in SCZ pathogenesis (Van Winkel ou al., 2008b). There are some pathophysiological changes in the key elements of “stress response system” during the advancement SCZ (Borges et approach., 2013, Holtzman et al., 2013, Pruessner et ing., 2017, Master et ing., 2008). For example , gene expression of glucocorticoid receptor (GR) decreases inside the limbic areas (Perlman et al., 2004, Webster ain al., 2002, Xing ou al., 2004) leading to exaggeration and elongation of anxiety responses (Phillips et approach., 2006). Because GR can be expressed inside the dopaminergic and dopaminoceptive circuitry (Corcoran ainsi que al., 2003), stress sensitization induced by glucocorticoids dysregulation may bring about a chute of incidents that finally lead to the dysregulation of dopaminergic program (Mizrahi ou al., 2018).

Catechol-O-Methyltransferase (COMT) is among the main players in the functionality of dopaminergic system (Abdolmaleky et ing., 2005, Howes et al., 2017). There are many research findings addressing changed COMT manifestation in different illnesses like SCZ (Abdolmaleky ain al., 2006, Matsumoto ain al., 2003b, Misiak ainsi que al., 2018, Tunbridge ainsi que al., 2004b) and Add Hyperactivity Disorder (ADHD) (Faraone et ing., 2014). Because of the scarcity of dopamine transporter in the frontal lobe, COMT is the main modulator of dopamine catabolism through this brain region (Wang ainsi que al., 1995). It has been recommended that, COMT hyperactivity plus the resultant enhancement of dopamine degradation inside the frontal bande is linked to disturbances in attention, professional cognition, and working memory performance in both controls and SCZ patients (Blasi et ‘s., 2005, Klosterbruder et al., 2005, Egan et ing., 2001, Frias et ing., 2005) that will be progressive over time (Frias ain al., 2005). Furthermore, COMT inhibitors may potentiate clozapine-induced dopamine launch and boost prefrontal bande performance (Tunbridge et ‘s., 2004a).

COMT gene has two main isoforms with independent promoters: Membrane-Bound COMT (MB-COMT) and Soluble COMT (S-COMT) (Tenhunen ainsi que al., 1994). MB-COMT is very important in SCZ pathogenesis as it is the main modulator of synaptic dopamine in the human brain (Matsumoto ou al., 2003a, Tenhunen ou al., 1994), which is up-regulated in SCZ (Nohesara et al., 2011). There are several polymorphisms in this gene, such as Val158Met (Chen ainsi que al., 2004). The Val158Met alleles code the enzymes with different numbers of physiological actions (Lachman et al., 1996). In addition , these types of alleles are participating differently in attention (Blasi et ‘s., 2005), cognition (Bruder ainsi que al., 2005, Egan ou al., 2001), emotion (Kempton et ing., 2009), reaction time (Stefanis et approach., 2005), character resilience (Kang et approach., 2013), originality seeking nature (Montag et al., 2012, Wingo ain al., 2016), harm elimination (Enoch et al., 2003), SCZ (Glatt et al., 2003, Kunugi et approach., 1997, Shifman et ing., 2004), and stress susceptibility in healthy individuals (Abdolmaleky et approach., 2006, Simons et al., 2009, Stefanis et al., 2007) and psychotic subject matter (Collip et al., 2011, Modinos ainsi que al., 2013, van Winkel et approach., 2008a). Likewise, it has been reported that a reduction in COMT level attenuates tension response in short-term, although increases tension susceptibility in the long term (Desbonnet et al., 2012).

Because SCZ is the outcome of gene-gene-environmental communications (Uher and Zwicker, 2017), there would be a large number of combinations of genes and environmental risk factors that may result in varied subtypes of SCZ based on a therapeutic remedies (Keshavan ainsi que al., 2017). Here, we all examined probably the most likely gene-environmental interactions, i. e. “dopamine and stress”, to clarify their roles in pressure induced vs . other SCZ patients. Although stress is a core of majority of environmental risk factors, “War Trauma” is a certain type of extreme stress which is not only perceived as a potential deadly physical pressure for very own self, yet also a main psychological stress related to the harm or loss of life of different combatants.

In this analyze, the COMT gene appearance was tested in the peripheral blood cells of four groupings, including 1) veterans diagnosed with SCZ following exposure to Iraq-Iran war because “stress-exposed SCZ” (S-SCZ), 2) their healthier brothers since “their genetically closest relatives” (S-Siblings), 3) SCZ patients with no good significant pressure as the non-stress exposed SCZ” (NoS-SCZ), and 4) the control subjects. In this article we evaluated the expression of COMT in blood skin cells, as a peripheral biomarker which may represent the brain’s malocclusions of COMT gene phrase (Luykx ain al., 2016). The non-affected siblings of S-SCZ had been included to look at whether a potential COMT expression alteration in S-SCZ can be described as familial trait that may predispose individuals to SCZ, secondary towards the war stress, and/or antipsychotic drugs. We also included NoS-SCZ patients to check into if potential alteration is usually specific for the stress induced SCZ or perhaps disease susceptibility, in general.


Based upon the effects of various other studies, we estimated the fact that number of 15 cases in each group is needed to provide a statistic power of 0. almost eight. For the omission of the monthly junk fluctuation result, only man subjects had been included. Those men were a total 66 male individuals inside the 35-to-63-year-oldage selection (Mean= forty-nine. 56, Standard Deviation= some. 92). Your research Ethics Committee of Tehran University of Medical Sciences approved this case-control analyze.

The typical exclusion conditions for all the organizations, based on the participants medical charts that were also affirmed by the sufferers and their families, were as follows: epilepsy, loss of consciousness, drug abuse, chemical tool injury, earlier history of significant head shock and brain injury (traumatic loss of mind, memory disruption or convulsion), any nerve disease, and past and family history of mental retardation. Diabetes mellitus, hypertension, hyperlipidemia, minor thalassemia or mild iron insufficiency anemia, smoking cigarettes, and good treatment with Electroconvulsive Remedy (ECT) weren’t considered as the exclusion criteria due to their large prevalence in the centre age or in SCZ patients. Yet , as shown in Table 1, the majority of these confounding factors existed in all analyze groups nearly equally. As well as the general exclusion criteria for a lot of groups, thyroid diseases, family (up with their third relatives) history of psychiatric disorder were considered as the exclusion conditions for the S-SCZ group. The exclusion criteria with the NoS-SCZ group were also similar to those of the S-SCZ group except that that they had no conflict trauma knowledge, plus the unfavorable familial great mental disorders was not regarded as an exemption criterion with this group.

In order to pick the patients for S-SCZ group, the hospital chart of 400 admitted or observed veterans of Iraq-Iran war were assessed. They were continuously assessed in Niayesh, Sadr, and Jannat hostipal wards. Among them, 150 cases were diagnosed because SCZ by psychiatrists together a mentally healthy guy sibling (brother) at the identical age group. Also these cases had displayed the disease symptoms during the first year following experiencing the battle trauma. Depending on Rahe’s mental stress conditions, the start symptoms in a stress-induced disease must be demonstrated in less than twelve months after the occurrence of tension (Spurgeon ain al., 2001). Finally, a total of seventeen cases had been found entitled to participation in S-SCZ group in line with the mandatory criteria in the study.

The second group consisted of the psychologically healthier male siblings of the S-SCZ group with similar environmental backgrounds yet no connection with war shock.

The cases intended for NoS-SCZ group were chosen from the SCZ patients who had been admitted to Roozbeh medical center (Tehran, Iran). Out of 200 guy SCZ sufferers with an age of40-to-60-years, 16 circumstances were identified eligible about the NoS-SCZ group criteria.

The subjects of the control group were sixteen healthy males of Roozbeh hospital staff, as presented by the Well being Department from the hospital and agreed to engage in this examine. They were needed to have no standard exclusion standards, no war trauma experience, and no psychiatric family history up to their third degree family members.

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