Decreased plasma adiponectin among male firefighters with symptoms of post-traumatic stress disorder

Pharmacological and physiological roles of adipokines and myokines in metabolic-related dementia

Dementia is a detrimental neuropathologic condition with considerable physical, mental, social, and financial impact on patients and society. Patients with metabolic syndrome (MetS), a group of diseases that occur in tandem and increase the risk of neurologic diseases, have a higher risk of dementia. The ratio between muscle and adipose tissue is crucial in MetS, as these contain many hormones, including myokines and adipokines, which are involved in crosstalk and local paracrine/autocrine interactions. Evidence suggests that abnormal adipokine and myokine synthesis and release may be implicated in various MetS, such as atherosclerosis, diabetic mellitus (DM), and dyslipidemia, but their precise role is unclear. Here we review the literature on adipokine and myokine involvement in MetS-induced dementia via glucose and insulin homeostasis regulation, neuroinflammation, vascular dysfunction, emotional changes, and cognitive function.

The sex-dependent response to psychosocial stress and ischaemic heart disease

Stress is an important risk factor for modern chronic diseases, with distinct influences in males and females. The sex specificity of the mammalian stress response contributes to the sex-dependent development and impacts of coronary artery disease (CAD). Compared to men, women appear to have greater susceptibility to chronic forms of psychosocial stress, extending beyond an increased incidence of mood disorders to include a 2- to 4-fold higher risk of stress-dependent myocardial infarction in women, and up to 10-fold higher risk of Takotsubo syndrome-a stress-dependent coronary-myocardial disorder most prevalent in post-menopausal women. Sex differences arise at all levels of the stress response: from initial perception of stress to behavioural, cognitive, and affective responses and longer-term disease outcomes. These fundamental differences involve interactions between chromosomal and gonadal determinants, (mal)adaptive epigenetic modulation across the lifespan (particularly in early life), and the extrinsic influences of socio-cultural, economic, and environmental factors. Pre-clinical investigations of biological mechanisms support distinct early life programming and a heightened corticolimbic-noradrenaline-neuroinflammatory reactivity in females vs. males, among implicated determinants of the chronic stress response. Unravelling the intrinsic molecular, cellular and systems biological basis of these differences, and their interactions with external lifestyle/socio-cultural determinants, can guide preventative and therapeutic strategies to better target coronary heart disease in a tailored sex-specific manner.

Prospective Association of Circulating Adipokines with Cardiometabolic Risk Profile Among Women: The Rape Impact Cohort Evaluation Study

BACKGROUND

Sexual violence is associated with poor cardiometabolic outcomes, yet the etiopathogenic pathways remain unclear. Adipokines may contribute to pathways in the development of cardiometabolic disease (CMD), including in vulnerable populations. Further investigation of adipokines among sexually traumatized individuals may inform cardiometabolic screening. This study aimed to investigate the association between circulating adipokines, metabolic syndrome (MetS), and longitudinal change in MetS components (namely abdominal obesity, blood pressure, lipid profile, and glycemic status) over a 1-year period in a cohort of rape exposed (RE) and rape unexposed (RUE) females.

MATERIALS AND METHODS

Seven hundred seventy-eight RE and 617 RUE black South African women aged 18-40 years were recruited for the Rape Impact Cohort Evaluation study. Nonfasting blood samples were analyzed for cardiometabolic variables and adipokine levels using enzyme-linked immunosorbent assay. Serum adiponectin was measured in both RE and RUE and resistin, leptin, and leptin/adiponectin (L/A) ratio in RE only. Associations between baseline serum adipokines, MetS, and its components were assessed at baseline and follow-up using adjusted linear and logistic regressions.

RESULTS

In the RE group, adiponectin, leptin, and L/A ratio were significantly associated with MetS prevalence cross-sectionally (all p ≤ 0.001). No adipokine marker was related to incident MetS at 12-month follow-up. In the RE group, significant longitudinal associations with high-density lipoprotein cholesterol were shown for adiponectin (β = 0.146 [0.064], p = 0.022) and leptin (β = 0.001 [0.002], p = 0.012).

CONCLUSIONS

Findings suggest that adipokines may have a potential role as biomarkers to identify RE individuals at high risk for CMD.

PGC-1α activity and mitochondrial dysfunction in preterm infants

Extremely low gestational age neonates (ELGANs) are born in a relatively hyperoxic environment with weak antioxidant defenses, placing them at high risk for mitochondrial dysfunction affecting multiple organ systems including the nervous, respiratory, ocular, and gastrointestinal systems. The brain and lungs are highly affected by mitochondrial dysfunction and dysregulation in the neonate, causing white matter injury (WMI) and bronchopulmonary dysplasia (BPD), respectively. Adequate mitochondrial function is important in providing sufficient energy for organ development as it relates to alveolarization and axonal myelination and decreasing oxidative stress via reactive oxygen species (ROS) and reactive nitrogen species (RNS) detoxification. Peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) is a master regulator of mitochondrial biogenesis and function. Since mitochondrial dysfunction is at the root of WMI and BPD pathobiology, exploring therapies that can regulate PGC-1α activity may be beneficial. This review article describes several promising therapeutic agents that can mitigate mitochondrial dysfunction through direct and indirect activation and upregulation of the PGC-1α pathway. Metformin, resveratrol, omega 3 fatty acids, montelukast, L-citrulline, and adiponectin are promising candidates that require further pre-clinical and clinical studies to understand their efficacy in decreasing the burden of disease from WMI and BPD in preterm infants.

Serum adiponectin-levels are predictive of probable posttraumatic stress disorder in women

Background

Accumulative evidence indicates a role for adiponectin, a polypeptide secreted by adipose tissue, in the pathophysiology of posttraumatic disorder (PTSD) via metabolic and inflammatory pathways. This study examined adiponectin as a potential predictive biomarker for PTSD among female rape survivors.

Methods

We evaluated the relationship of baseline serum adiponectin levels to the development of probable PTSD at 3- and 6-months post rape-exposure and compared adiponectin levels between 542 rape-exposed (RE) and 593 rape-unexposed women (RUE). Probable PTSD were defined as Davidson Trauma Scale score ≥40. Data were analysed using multivariate regression models and a generalized estimating equation (GEE) model. We adjusted for clinically relevant covariates associated with PTSD, as well as adiposity indices.

Results

Participants who were in the mid-and high adiponectin tertile groups versus the lowest tertile group had a significantly reduced risk of probable PTSD among at 6 months follow-up, independent of adiposity(aOR = 0.45[0.22–1.05], p = 0.035; aOR = 0.44[0.22–0.90], p = 0.024). However, there was no effect of group (RE vs. RUE).

Limitations

Adiponectin assays were conducted on non-fasting blood samples and information on chronic medication, dietary factors and levels of physical activity were not collected. There was a high attrition rate among rape exposed participants.

Conclusions

Our results show that higher serum adiponectin levels are associated with reduced risk of probable PTSD over a 6-month period. This finding supports the hypothesis that serum adiponectin is a potential risk biomarker for PTSD.

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The prospective associations between adiponectin, an anti-inflammatory cytokine and development of PTSD was examined in a cohort of rape exposed women.

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Serum adiponectin levels were inversely associated with probable PTSD at 6 month among control but not rape exposed women.

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Results suggest that adiponectin may serve as a potential risk biomarker of PTSD.

Central Adiponectin Signaling – A Metabolic Regulator in Support of Brain Plasticity

Brain plasticity and metabolism are tightly connected by a constant influx of peripheral glucose to the central nervous system in order to meet the high metabolic demands imposed by neuronal activity. Metabolic disturbances highly affect neuronal plasticity, which underlies the prevalent comorbidity between metabolic disorders, cognitive impairment, and mood dysfunction. Effective pro-cognitive and neuropsychiatric interventions, therefore, should consider the metabolic aspect of brain plasticity to achieve high effectiveness. The adipocyte-secreted hormone, adiponectin, is a metabolic regulator that crosses the blood-brain barrier and modulates neuronal activity in several brain regions, where it exerts neurotrophic and neuroprotective properties. Moreover, adiponectin has been shown to improve neuronal metabolism in different animal models, including obesity, diabetes, and Alzheimer’s disease. Here, we aim at linking the adiponectin’s neurotrophic and neuroprotective properties with its main role as a metabolic regulator and to summarize the possible mechanisms of action on improving brain plasticity via its role in regulating the intracellular energetic activity. Such properties suggest adiponectin signaling as a potential target to counteract the central metabolic disturbances and impaired neuronal plasticity underlying many neuropsychiatric disorders.

A Scoping Review on the Prevalence and Determinants of Post-Traumatic Stress Disorder among Military Personnel and Firefighters: Implications for Public Policy and Practice

Introduction: Firefighters and military personnel are public safety personnel who protect the safety of individuals and their properties. They are usually exposed to traumatic events leaving them at risk of developing mental health conditions such as post-traumatic stress disorder (PTSD). Increasing concern is being raised regarding the mental health impacts, specifically PTSD, among military personnel and firefighters. Objective: There is an increased exposure of firefighters and military personnel to traumatic events and the attendant risk of developing post-traumatic stress disorder. It is crucial to ascertain the level of PTSD amongst this cohort and determinants to formulate policies and practices that mitigate the risk and protect public safety personnel. This scoping review sought to determine the prevalence of PTSD among this cohort globally and to explore determinants of this mental health condition. Methods: A literature search in databases including MEDLINE, CINAHL, PubMed, PsycINFO, and EMBASE was conducted electronically from May 2021 to 31 July 2021. Two reviewers independently assessed full-text articles according to the predefined inclusion criteria and screening process undertaken to identify studies for the review. Articles were screened with a third reviewer, resolving conflicts where necessary and further assessing them for eligibility. During article selection, the PRISMA checklist was adopted, and with the Covidence software, a total of 32 articles were selected for the final examination. For the eligible studies, data extraction was conducted, information was collated and summarized, and the findings were reported. Original qualitative and quantitative data on the prevalence and predictors of PTSD among veterans, military, and firefighters were reported. Results: The prevalence of PTSD was 57% for firefighters and 37.8% for military personnel. Demographic factors, job factors, social support, injuries, physical and psychological factors, and individual traits were the main predictors of PTSD in this cohort. Conclusion: This information is vital for developing and implementing prevention and intervention strategies for PTSD in military personnel and firefighters. Recognizing and addressing factors that predict PTSD will help to improve mental wellbeing and increase productivity. More peer-reviewed studies are needed on the prevalence of PTSD amongst these cohorts.

Comparison of Peripheral Biomarkers and Reduction of Stress Response in Patients With Major Depressive Disorders vs. Panic Disorder

Alteration in stress response seems to affect the development of psychiatric disorders. In this study, we aimed to investigate whether baseline peripheral biomarkers could predict the reduction of stress response among patients with major depressive disorder (MDD) and panic disorder (PD). Patients with MDD (n = 41) and PD (n = 52) and healthy controls (HC, n = 59) were selected and regularly followed up with five visits for 12 weeks. The severity of stress at every visit was assessed using the Stress Response Inventory (SRI), and peripheral biomarkers were measured by blood tests at baseline and 2, 4, 8, and 12 weeks. Interleukin (IL)-6, IL-10, tumor necrosis factor (TNF)-α, interferon (IFN)-γ, C-reactive protein (CRP), adiponectin, and leptin levels were analyzed using enzyme-linked immunosorbent assays. Reduction of stress response was defined as the difference in SRI score between baseline and 12 weeks divided by the baseline score. SRI scores were significantly (p < 0.0001) higher in patients with MDD and PD than in HC at every visit after adjusting for variables. In multivariable linear regression, adiponectin levels at baseline were significantly associated with reduction of stress response in patients with PD. When adiponectin increased 1 mg/l, stress response decreased 0.781 points (β = -0.781, S.E. = 0.220, p = 0.001). Among the subscales of SRI, somatization had a moderate negative correlation with adiponectin levels (r = -0.469). There was no significant association between baseline peripheral biomarkers and reduction of stress response in patients with MDD. Our study showed an inverse association between baseline adiponectin levels and stress response changes in patients with PD, but not in patients with MDD. Thus, differentiated approaches for assessing and treating stress responses of patients with PD and MDD might be helpful. Larger and longitudinal studies are necessary to establish the role and mechanism of action of adiponectin in regulating stress responses in PD.

Adiponectin gene polymorphisms and posttraumatic stress disorder symptoms among female rape survivors: an exploratory study

Background: Rape is a common traumatic event which may result in the development of posttraumatic stress disorder (PTSD), yet few studies have investigated risk biomarkers in sexually traumatised individuals. Adiponectin is a novel cytokine within inflammatory and cardiometabolic pathways with evidence of involvement in PTSD. Objective: This prospective exploratory study in a sample of female rape survivors investigated the association of single nucleotide polymorphisms (SNPs) in the adiponectin gene (ADIPOQ) and posttraumatic stress symptom (PTSS) severity, and the interaction of these SNPs of interest with childhood trauma in modifying the association with PTSS severity. Method: The study involved 455 rape-exposed black South African women (mean age (SD), 25.3 years (±5.5)) recruited within 20 days of being raped. PTSS was assessed using the Davidson Trauma Scale (DTS) and childhood trauma was assessed using a modified version of the Childhood Trauma Scale-Short Form Questionnaire. Eight ADIPOQ SNPs (rs17300539, rs16861194, rs16861205, rs2241766, rs6444174, rs822395, rs1501299, rs1403697) were genotyped using KASP. Mixed linear regression models were used to test additive associations of ADIPOQ SNPs and PTSS severity at baseline, 3 and 6 months following rape. Results: The mean DTS score post-sexual assault was high (71.3 ± 31.5), with a decrease in PTSS severity shown over time for all genotypes. rs6444174TT genotype was inversely associated with baseline PTSS in the unadjusted model (β = -13.6, 95% CI [-25.1; -2.1], p = .021). However, no genotype was shown to be significantly associated with change in PTSS severity over time and therefore ADIPOQ SNP x childhood trauma interaction was not further investigated. Conclusion: None of the ADIPOQ SNPs selected for investigation in this population were shown to be associated with change in PTSS severity over a 6-month period and therefore their clinical utility as risk biomarkers for rape-related PTSD appears limited. These SNPs should be further investigated in possible gene-gene and gene-environment interactions.

Peripheral adiponectin levels in anxiety, mood, trauma- and stressor-related disorders: A systematic review and meta-analysis

BACKGROUND

Anxiety, mood, trauma- and stressor-related disorders confer increased risk for metabolic disease. Adiponectin, a cytokine released by adipose tissue is associated with these disorders and obesity via inflammatory processes. Available data describing associations with mental disorders remain limited and conflicted.

METHODS

A systematic search was conducted for English, peer-reviewed articles from inception until February 2019 that assessed for serum or plasma adiponectin levels in adults with an anxiety, mood or trauma-related disorder. Diagnoses were determined by psychiatric interview, based on DSM-IV, DSM-5 or ICD-10 criteria. Analyses were performed using STATA 15 and Standardized mean difference (SMD) with 95% confidence interval was applied to pool the effect size of meta-analysis studies.

RESULTS

In total 65 eligible studies were included in the systematic review and 30 studies in this meta-analysis. 19,178 participants (11,262 females and 7916 males), comprising healthy adults and adults with anxiety, mood and trauma-related disorders, were included. Overall results indicated an inverse association between adiponectin levels and examined mental disorders. Specifically, patients with an anxiety disorder (SMD  = -1.18 µg/mL, 95% CI, -2.34; -0.01, p  = 0.047); trauma or stressor-related disorder (SMD  =  -0.34 µg/mL, 95% CI, -0.52; -0.17, p  = 0.0000) or bipolar disorder (SMD  =  -0.638 µg/mL, 95% CI, -1.16, -0.12, p  = 0.017) had significant lower adiponectin levels compared to healthy adults.

LIMITATIONS

Heterogeneity, potential publication bias, and lack of control for important potential confounders were significant limitations.

CONCLUSION

Peripheral adiponectin levels appear to be inversely associated with anxiety, mood, trauma- and stressor related disorders and may be a promising biomarker for diagnosis and disease monitoring.

[Adiponectin: an endogenous molecule with anti-inflammatory and antidepressant properties?]

Adiponectin (ApN) is a hormone produced by adipose tissue, yet the plasma level of ApN is decreased in overweight and obese people, as well as in people with diabetes. In the periphery, this decrease in circulating levels of ApN induces the establishment of a chronic low-grade inflammatory state and is involved in the development of insulin resistance and atheromas. Conversely, "favorable" living conditions, weight loss and regular physical exercise increase ApN blood concentration. Some forms of ApN can reach the brain parenchyma through the cerebrospinal fluid. In the brain, the increase in ApN exerts powerful antidepressant and anxiolytic effects, in particular by fighting against neuroinflammation.

Dual-therapy strategy for modification of adiponectin receptor signaling in aging-associated chronic diseases

Given the paradigm of anti-insulin resistance in therapies for metabolic syndrome, there has been considerable interest in adiponectin (APN), an adipocyte-derived sensitizer of insulin receptor signaling. In contrast to hypoadiponectinemia in metabolic syndrome, evidence suggests that Alzheimer's disease (AD) and other diseases, including chronic heart failure (CHF) and chronic kidney disease (CKD), are characterized by hyperadiponectinemia as well as the APN/obesity paradoxes, indicating that a decrease in APN might also be beneficial for these diseases. Thus, distinct from metabolic syndrome, it is anticipated that APN receptor antagonists rather than agonists might be effective in therapy for some chronic diseases.