Methylation of the AIM2 gene: An epigenetic mediator of PTSD-related inflammation and neuropathology plasma biomarkers

Clinical potential of epigenetic and microRNA biomarkers in PTSD

Molecular studies identifying alterations associated with PTSD have predominantly focused on candidate genes or conducted genome-wide analyses, often encountering issues with replicability. This review aims to identify robust bi-directional epigenetic and microRNA (miRNA) regulators focusing on their functional impacts on post-traumatic stress disorder (PTSD) and their utility in clinical diagnosis, whilst examining knowledge gaps in the existing research. A systematic search was conducted across multiple databases, including Web of Science, Scopus, Global Health (CABI), and PubMed, augmented by grey literature, yielding 3465 potential articles. Ultimately, 92 studies met the inclusion criteria and were analysed to pinpoint significant epigenetic changes with clinically relevant potential in PTSD. The selected studies explored histone modifications, CpG sites, single nucleotide polymorphisms (SNPs), and miRNA biomarkers. Specifically, nine studies examined epigenetic markers, detailing the influence of methylation on chromatin accessibility at histone positions H3K4, H3K9, and H3K36 within a PTSD context. Seventy-three studies investigated DNA methylation, identifying 20 hypermethylated and five hypomethylated CpG islands consistently observed in PTSD participants. Nineteen studies linked 88 SNPs to PTSD, with only one SNP replicated within these studies. Furthermore, sixteen studies focused on miRNAs, with findings indicating 194 downregulated and 24 upregulated miRNAs were associated with PTSD. Although there are epigenetic mechanisms that are significantly affected by PTSD, a granular deconstruction of these mechanisms elucidates the need to incorporate more nuanced approaches to identifying the factors that contribute to PTSD. Technological advances in diagnostic tools are driving the need to integrate detailed participant characteristics, trauma type, genetic susceptibilities, and best practices for robust reporting. This comprehensive approach will be crucial for enhancing the translational potential of PTSD research for clinical application.

Heparin as a Potential Therapeutic Substance for Post-Traumatic Stress Disorder

In sexually mature male Wistar rats with modeled post-traumatic stress disorder, personalized characteristics of neurobiological reactions in the population of predator-induced stress-resilient and stress-susceptible heparinized animals were determined. Characteristics of the systemic response of immune mechanisms, hypothalamic-pituitary-adrenal axis, behavioral manifestations, as well as basic properties of the CNS (excitation/inhibition) are presented. The study demonstrated encouraging positive results of the course administration of unfractionated heparin at a dose below the therapeutic and prophylactic doses. The inclusion of heparin drugs into the clinical practice for the treatment of post-traumatic stress disorder will not require large-scale clinical trials, because many effects of heparin as a nonspecific adaptogen are well studied. Moreover, these properties were confirmed at a higher technological level during the COVID-19 pandemic.

Bridging the Gap: Investigating the Link between Inflammasomes and Postoperative Cognitive Dysfunction

Postoperative cognitive dysfunction (POCD) is a cluster of cognitive problems that may arise after surgery. POCD symptoms include memory loss, focus inattention, and communication difficulties. Inflammasomes, intracellular multiprotein complexes that control inflammation, may have a significant role in the development of POCD. It has been postulated that the NLRP3 inflammasome promotes cognitive impairment by triggering the inflammatory response in the brain. Nevertheless, there are many gaps in the current literature to understand the underlying pathophysiological mechanisms and develop future therapy. This review article underlines the limits of our current knowledge about the NLRP3 (NOD-, LRR- and pyrin domain-containing protein 3) inflammasome and POCD. We first discuss inflammasomes and their types, structures, and functions, then summarize recent evidence of the NLRP3 inflammasome's involvement in POCD. Next, we propose a hypothesis that suggests the involvement of inflammasomes in multiple organs, including local surgical sites, blood circulation, and other peripheral organs, leading to systemic inflammation and subsequent neuronal dysfunction in the brain, resulting in POCD. Research directions are then discussed, including analyses of inflammasomes in more clinical POCD animal models and clinical trials, studies of inflammasome types that are involved in POCD, and investigations into whether inflammasomes occur at the surgical site, in circulating blood, and in peripheral organs. Finally, we discuss the potential benefits of using new technologies and approaches to study inflammasomes in POCD. A thorough investigation of inflammasomes in POCD might substantially affect clinical practice.

Advances in the molecular neurobiology of posttraumatic stress disorder from global contexts: A systematic review of longitudinal studies

Trauma exposure is prevalent globally and is a defining event for the development of posttraumatic stress disorder (PTSD), characterised by intrusive thoughts, avoidance behaviours, hypervigilance and negative alterations in cognition and mood. Exposure to trauma elicits a range of physiological responses which can interact with environmental factors to confer relative risk or resilience for PTSD. This systematic review summarises the findings of longitudinal studies examining biological correlates predictive of PTSD symptomology. Databases (Pubmed, Scopus and Web of Science) were systematically searched using relevant keywords for studies published between 1 January 2021 and 31 December 2022. English language studies were included if they were original research manuscripts or meta-analyses of cohort investigations that assessed longitudinal relationships between one or more molecular-level measures and either PTSD status or symptoms. Eighteen of the 1,042 records identified were included. Studies primarily included military veterans/personnel, individuals admitted to hospitals after acute traumatic injury, and women exposed to interpersonal violence or rape. Genomic, inflammation and endocrine measures were the most commonly assessed molecular markers and highlighted processes related to inflammation, stress responding, and learning and memory. Quality assessments were done using the Systematic Appraisal of Quality in Observational Research, and the majority of studies were rated as being of high quality, with the remainder of moderate quality. Studies were predominantly conducted in upper-income countries. Those performed in low- and middle-income countries were not broadly representative in terms of demographic, trauma type and geographic profiles, with three out of the four studies conducted assessing only female participants, rape exposure and South Africa, respectively. They also did not generate multimodal data or use machine learning or multilevel modelling, potentially reflecting greater resource limitations in LMICs. Research examining molecular contributions to PTSD does not adequately reflect the global burden of the disorder.

Psychological and biological mechanisms linking trauma with cardiovascular disease risk

Cardiovascular disease (CVD) is the leading cause of death and disability worldwide, and experiences of psychological trauma have been associated with subsequent CVD onset. Identifying key pathways connecting trauma with CVD has the potential to inform more targeted screening and intervention efforts to offset elevated cardiovascular risk. In this narrative review, we summarize the evidence for key psychological and biological mechanisms linking experiences of trauma with CVD risk. Additionally, we describe various methodologies for measuring these mechanisms in an effort to inform future research related to potential pathways. With regard to mechanisms involving posttraumatic psychopathology, the vast majority of research on psychological distress after trauma and CVD has focused on posttraumatic stress disorder (PTSD), even though posttraumatic psychopathology can manifest in other ways as well. Substantial evidence suggests that PTSD predicts the onset of a range of cardiovascular outcomes in trauma-exposed men and women, yet more research is needed to better understand posttraumatic psychopathology more comprehensively and how it may relate to CVD. Further, dysregulation of numerous biological systems may occur after trauma and in the presence of posttraumatic psychopathology; these processes of immune system dysregulation and elevated inflammation, oxidative stress, mitochondrial dysfunction, renin-angiotensin system dysregulation, and accelerated biological aging may all contribute to subsequent cardiovascular risk, although more research on these pathways in the context of traumatic stress is needed. Given that many of these mechanisms are closely intertwined, future research using a systems biology approach may prove fruitful for elucidating how processes unfold to contribute to CVD after trauma.

AIM2 and Psoriasis

Psoriasis is a chronic inflammatory skin disease occurring worldwide, with multiple systemic complications, which seriously affect the quality of life and physical and mental health of patients. The pathogenesis of psoriasis is related to the environment, genetics, epigenetics, and dysregulation of immune cells such as T cells, dendritic cells (DCs), and nonimmune cells such as keratinocytes. Absent in melanoma 2 (AIM2), a susceptibility gene locus for psoriasis, has been strongly linked to the genetic and epigenetic aspects of psoriasis and increased in expression in psoriatic keratinocytes. AIM2 was found to be activated in an inflammasome-dependent way to release IL-1β and IL-18 to mediate inflammation, and to participate in immune regulation in psoriasis, or in an inflammasome-independent way by regulating the function of regulatory T(Treg) cells or programming cell death in keratinocytes as well as controlling the proliferative state of different cells. AIM2 may also play a role in the recurrence of psoriasis by trained immunity. In this review, we will elaborate on the characteristics of AIM2 and how AIM2 mediates the development of psoriasis.