Associations of age, sex and body mass index to brain [11C]-UCB-J PET in first episode psychosis patients and healthy controls

Abstract

Psychotic disorders are a complex, multifactorial group of disorders that are caused by both genetic and environmental factors. Although the underlying biochemical mechanisms are poorly understood, disturbed neuronal connectivity and altered synaptic density have been proposed to play key roles in the etiology of this group of severe illnesses. For example, post-mortem and animal studies show evidence of a lowered synaptic density in psychosis patients and schizophrenia animal models. Recent advancements in radiotracer development presents to us the opportunity to investigate synapses in vivo; [11C]-UCB-J is a rather new radiotracer used in positron emission tomography (PET) imaging. It targets a ubiquitously expressed synaptic vesicle protein 2A (SV2A) in the human brain. This has been proposed to represent synaptic density. However, common demographic variables, such as age, can plausibly confound these measurements of synaptic density. We researched associations of relevant demographic factors age, sex, BMI and injected dose to [11C]-UCB-J binding in first episode psychosis patients (FEP) and healthy controls. This study broadens our knowledge of the possible pitfalls and confounding factors in clinical studies using [11C]-UCB-J and PET.