Chronic Variable Stress Induces Hepatic Fe(II) Deposition by Up-Regulating ZIP14 Expression via miR-181 Family Pathway in Rats

It is well-known that hepatic iron dysregulation, which is harmful to health, can be caused by stress. The aim of the study was to evaluate chronic variable stress (CVS) on liver damage, hepatic ferrous iron deposition and its molecular regulatory mechanism in rats. Sprague Dawley rats at seven weeks of age were randomly divided into two groups: a control group (Con) and a CVS group. CVS reduces body weight, but increases the liver-to-body weight ratio. The exposure of rats to CVS increased plasma aspartate aminotransferase (AST), alkaline phosphatase (ALP) and hepatic malondialdehyde (MDA) levels, but decreased glutathione peroxidase (GSH-Px) activity, resulting in liver damage. CVS lowered the total amount of hepatic iron content, but induced hepatic Fe(II) accumulation. CVS up-regulated the expression of transferrin receptor 1 (TFR1) and ZRT/IRT-like protein 14 (ZIP14), but down-regulated ferritin and miR-181 family members. In addition, miR-181 family expression was found to regulate ZIP14 expression in HEK-293T cells by the dual-luciferase reporter system. These results indicate that CVS results in liver damage and induces hepatic Fe(II) accumulation, which is closely associated with the up-regulation of ZIP14 expression via the miR-181 family pathway.

Amelioration on oxidative stress, testosterone, and cortisol levels after administration of Vitamins C and E in albino rats with chronic variable stress

Background and Aim: Stress can cause physiological and biological disorders in the body. On the other hand, antioxidants from vitamins and minerals are effective for stress treatment. Therefore, this study aimed to evaluate the effect of the administration of Vitamins C and E on serum superoxide dismutase (SOD), malondialdehyde (MDA), catalase (CAT), glutathione peroxidase (GPx), testosterone, and cortisol activity in albino rats with chronic variable stress (CVS). Materials and Methods: Twenty albino rats were randomly assigned into four treatment groups: C was administered normal saline; T1 was administered Vitamins C and E; T2 was only induced CVS; and T3 was induced CVS followed by Vitamins C and E administration. All treatments were applied for 4 weeks, respectively. Furthermore, 5 mL of blood samples were collected intracardially. Body weight data were collected for the initial and final weights. From serum samples, SOD, GPx, and CAT were measured using the enzymol method; MDA was measured using the high-performance liquid chromatography method; and testosterone and cortisol were measured using the enzyme-linked immunosorbent assay method. All variables were analyzed statistically using analysis of variance followed by the Duncan test (p<0.05). Results: Our findings showed that the T1 and T3 groups significantly decreased (p<0.001) compared to T2 in the following parameters: SOD, MDA, GPx, and cortisol. Meanwhile, CAT and testosterone levels in the T1 and T3 groups were significantly increased (p<0.001) compared to the T2 group. In addition, the weight gain in T1 and T3 groups was significantly increased (p<0.001) compared to T2 group. Conclusion: It can be concluded that the administration of Vitamins C and E had a significant effect to alleviate SOD, MDA, GPx, and cortisol and to improve the testosterone level in albino rats with CVS.

Abstract 17234: Elevated Atherosclerotic Biomarkers in Mice With Mild Blast Traumatic Brain Injury and Chronic Variable Stress

Introduction: Traumatic brain injury (TBI) and stress are significant health concerns that have atherosclerotic cardiovascular disease (ASCVD) effects. Stress and injury can elevate neurochemicals and hormones in the brain that lead to dysfunction of the hypothalamic-pituitary-adrenal axis and the autonomic nervous system increasing inflammation, which plays a role in the development of ASCVD. Animal models can provide a method of separating mild TBI (mTBI) from models of chronic stress. Hypothesis: We hypothesize that mild blast TBI (mbTBI) and chronic variable stress (CVS) will result in elevated ASCVD biomarkers in mice. Methods: Frozen hearts from C57BL/6J mice (8 weeks, N=16, 8 male/8 randomly cycling female) were obtained through an IACUC approved study. The C57BL/6J mice were part of a mild blast TBI (mbTBI) study utilizing a blast chamber to receive a short duration shock wave (<10 msec, mean peak pressure of blast waves 19.9 psi). A group was subjected to CVS for two weeks prior to the blast, plus one week after blast. All groups were followed for four weeks. Western Blots with relative expression (normalized) were performed using an infrared imaging system. ERK1, ERK2, Galactein 3, Endothelin-1, BDNF, NT-Pro-BNP, and NRG1. ANOVA with Tukey HSD correction and descriptive statistics were performed using SPSS with significance by α of 0.05. Results: ERK1: mbTBI and CVS (p<0.05). CVS +mbTBI to CVS (0.015)( p<0.05 ), compared to mbTBI (0.017). ERK2: mbTBI sham = 0.009, CVS only = 0.008, mbTBI only = 0.008 and CVS + mbTBI = 0.012. Galectin-3 (Gal-3): CVS only = 0.144, CVS+mbTBI = 0.168, mbTBI (0.114) to sham (0.111) ( p<0.05 ). NT-Pro-BNP: CVS+mbTBI = 0.168, sham 0.076. mbTBI alone (0.077) and CVS alone (0.078). NRG1: mbTBI (0.195) and mbTBI with CVS (0.178). CVS only group (0.157). ET-1: mbTBI sham = 0.068, CVS only = 0.080 mbTBI only = 0.084 and CVS+mbTBI = 0.134. BDNF: CVS only = 0.053, CVS+mbTBI = 0.069. Sham group (0.047), mbTBI (0.038). Conclusion: Our results on proteins related to a broad spectrum of vascular growth, innervation, function, inflammation and markers of atherosclerotic plaque development suggest that mbTBI and/or chronic stress may increase risk for developing early ASCVD.

Abstract 17179: Stress-Mediated Platelet Activation Contributes to Thrombosis: Findings From the American Heart Association Go Red for Women Strategically Focused Research Network

Background: Psychological stress is a risk factor for cardiovascular disease (CVD). Despite advancements in CV-prevention, CVD remains the global leading cause of disease burden, suggesting that additional factors contribute to sustained CV risk. The mechanisms by which stress contributes to increased CVD are largely unknown. However, in preclinical models increased sympathetic nervous system activity promotes systemic inflammation (e.g. monocyte activation, cytokine production), and may underlie increased CVD risk. We investigated perceived stress in women with MI and its association with platelet activity, and validated our findings in a murine model. Methods: Monocyte-platelet aggregates (MPA) and psychological stress, using the validated Perceived Stress Scale (PSS4), were measured in women post MI (n=96; median age 62.2 years) and in control women (n=31; 66.7 years). A mouse model of chronic variable stress was utilized to explore the impact of stress on platelet activity and risk of thrombosis-mediated death. Results: Perceived stress was higher in MI patients than matched women (p=0.009). Platelet activity, assessed by MPA, was significantly elevated in MI vs. controls (p=0.0025). MPA significantly correlated with PSS4 scores (R=0.412, p =0.009). In a female mouse model of chronic variable stress, circulating MPA was increased in stressed mice compared to controls (p<0.05), and platelet activation markers P-selectin and JON/A were increased on platelets from stressed mice relative to stress free mice (p<0.05). Using a platelet mediated thrombosis model, time to thrombosis and survival was reduced in stressed mice. Conclusion: Platelet activity was increased at the time of MI in women, and positively associated with stress. In a mouse model, we find that stress is a significant contributor to increased platelet reactivity, and promotes thrombosis-mediated death. Cross-talk between platelets and monocytes is a critical mechanism linking thrombosis and inflammation, thus stress-induced MPAs may represent an unexplored pathway linked to stress-mediated CVD-risk. Future studies will examine whether reducing stress reduces platelet hyperactivity and MI risk.

Chronic stress induces sex-specific functional and morphological alterations in cortico-accumbal and cortico-tegmental pathways

BackgroundThe medial prefrontal cortex (mPFC) is part of a complex circuit controlling stress responses by sending projections to different limbic structures including the nucleus accumbens (NAc) and ventral tegmental area (VTA). However, the impact of chronic stress on NAc- and VTA-projecting mPFC neurons is still unknown and the distinct contribution of these pathways to stress responses in males and females is unclear.MethodsBehavioral stress responses were induced by 21 days of chronic variable stress (CVS) in male and female C57BL6 mice. An inter-sectional viral approach was used to label both pathways and assess the functional, morphological, and transcriptional adaptations in NAc- and VTA-projecting mPFC neurons in stressed males and females. Using chemogenetic approaches, we modified neuronal activity of NAc-projecting mPFC neurons to decipher their contribution to stress phenotypes.ResultsCVS induced depressive-like behaviors in males and females. NAc- and VTA-projecting mPFC neurons exhibited sex-specific functional, morphological, and transcriptional alterations. The functional changes were more severe in females in NAc-projecting mPFC neurons while males exhibited more drastic reductions in dendritic complexity in VTA-projecting mPFC neurons after CVS. Finally, chemogenetic overactivation of the cortico-accumbal pathway triggered anxiety and behavioral despair in both sexes while its inhibition rescued the phenotype only in females.ConclusionsOur results suggest that by changing the activity of transcriptional programs controlling neuronal plasticity, CVS interferes with the morphological and synaptic properties of the cortico-accumbal and tegmental pathways differently in males and females contributing to the expression of anxiety and depressive-like behaviors distinctly in a sex-specific fashion.