engleski

The association between platelet MAO-B activity and specific symptoms in PTSD

Introduction: Posttraumatic stress disorder (PTSD) is an anxiety disorder that can develop in some subjects after exposure to extreme trauma. The most common symptoms of PTSD are re-experiencing of the traumatic event(s), avoidance of trauma stimuli, numbing and persistent hyperarousal that are present for at least a month. Since not all subjects exposed to a trauma develop PTSD, and some individuals with PTSD also develop comorbidities such as major depression, panic disorder, agitation, cognitive impairment, psychosis, drug and alcohol abuse and suicidal behavior, the extent to which individuals are vulnerable or resilient depends on different psychosocial, biological, environmental, genetic and epigenetic factors, and the complex interaction between them. Monoamine oxidase (MAO) isoenzymes type A and type B degrade serotonin, noradrenaline (mostly MAO-A) and dopamine (primarily MAO-B) and other amines. There are reports of the association between altered platelet MAO-B activity and changes in mood, behavior, and various symptoms in different neuropsychiatric disorders. The aim of this study was to investigate the association of platelet MAO-B activity and several symptoms occurring in PTSD defined with the Positive and Negative Syndrome Scale (PANSS) and its subscales. Methods: Proposed study included 459 male war veterans with PTSD of the Croatian origin. The diagnoses of PTSD and comorbid psychiatric disorders have been made using Structured Clinical Interview (SCID) based on DSM-IV criteria, Clinician Administered PTSD Scale (CAPS), PANSS and its positive, negative, general, excitement, psychosis, depression and cognitive subscales. MAO-B activity was determined with spectrofluorometric method, using kynuramine as a substrate, from platelet- rich plasma, obtained through series of centrifugation of whole blood samples. Due to deviation from normal distribution, non- parametric statistical analysis was used (SigmaStat 3.5). This work was supported by Croatian Science Foundation grant IP-2014-09- 4289. Results: As expected, MAO-B activity was significantly decreased in smokers, hence whole analysis was done in smokers and non-smokers separately. All subjects were subdivided into groups with moderate and severe symptoms and those with none or mild symptoms. Platelet MAO- B activity was significantly decreased in smokers with moderate and severe symptoms of agitation vs. those with mild symptoms of agitation. Platelet MAO-B activity was drastically lower in individuals with higher psychotic, depressive, positive, general and total PANSS scores than in those with mild symptoms. Symptoms listed in the PANSS cognitive and negative subscale were not significantly associated with platelet MAO-B activity. Conclusion: Since MAO-B degrades dopamine, lower MAO-B activity can lead to higher dopamine availability in the prefrontal cortex, which might be associated with elevated psychosis and agitation levels. To elucidate the role of platelet MAO-B in development and severity of different symptoms occurring in PTSD, but also in other neuropsychiatric disorders, further studies should be focused on more specific clinical measures, and should also include genetic analysis of MAO-B variants.

PTSD ; platelet MAO-B ; PTSD comorbidities ; psychosis ; agitation

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