No abstract

Cell free DNAs (cfDNA) are short DNA fragments which are present in all biological fluids and cell culture medium. They were first detected in blood plasma by Mandel and Metais in 1948. cfDNAs are mostly endogenous-derived fragments that are determined in lipid/protein rich complexes or particles with membranes. In healthy individuals, there are small amounts of mono-nucleosome forms of cfDNA in the peripheral circulation. cfDNA can bind to proteins and phospholipids on cell surfaces. This mechanism may related to absorbance and release of cfDNA. Different enzymes such as deoxyribonuclease (DNase) may facilitate the unbounding and recirculation of membrane bound cfDNAs.

Extracellular Genomic Materials (EGMs) are the nucleic acids secreted or released from all types of cells by endogenous or exogenous stimuli through varying mechanisms into the extracellular region and inevitably to all biological fluids. EGMs could be found as free, protein-bound, and/ or with vesicles. EGMs can potentially have immunophenotypic and/or genotypic characteristics of a cell of origin, travel to distant organs, and interact with the new microenvironment. To achieve all, EGMs might bi-directionally transit through varying membranes, including the blood–brain barrier. Such ability provides the transfer of any information related to the pathophysiological changes in psychiatric disorders in the brain to the other distant organ systems or vice versa. In this article, many aspects of EGMs have been elegantly reviewed, including their potential in diagnosis as biomarkers, application in treatment modalities, and functional effects in the pathophysiology of psychiatric disorders. The psychiatric disorders were studied under subgroups of Schizophrenia spectrum disorders, bipolar disorder, depressive disorders, and an autism spectrum disorders. EGMs provide a robust and promising tool in clinics for prognosis and diagnosis. The successful application of EGMs into treatment modalities might further provide encouraging outcomes for researchers and clinicians in psychiatric disorders.