Effect of depression and sertraline treatment on cardiac function in female nonhuman primates

Psychosocial stress increases risk for type 2 diabetes in female cynomolgus macaques consuming a western diet

Chronic psychosocial stress is associated with increased risk of many chronic diseases including type 2 diabetes mellitus. However, it is difficult to establish a causal relationship between stress and diabetes in human studies because stressors often are self-reported and may be distant in time from metabolic consequences. Macaques are useful models of the effects of chronic psychosocial stress on health and may develop obesity and diabetes similar to human beings. Thus, we studied the relationships between social subordination stress - a well-validated psychological stressor in macaques - and body composition and carbohydrate metabolism in socially housed, middle-aged female cynomolgus monkeys (Macaca fascicularis; n = 42). Following an 8-week baseline phase, the monkeys were fed a Western diet for 36 months (about equivalent to 10 human years). Social status was determined based on the outcomes of agonistic interactions (X¯= 33.3 observation hours/monkey). Phenotypes collected included plasma cortisol, body composition, circulating markers of glucose metabolism, activity levels, and heart rate variability measured as RMSSD (root of mean square of successive differences) and SDDN (standard deviation of beat to beat interval) after 1.5- and 3-years on diet. Mixed model analyses of variance revealed that aggression received, submissions sent, and cortisol were higher, and RMSSD and SDNN were lower in subordinates than dominants (social status: p < 0.05). After 3 years of Western diet consumption, fasting triglyceride, glucose and insulin concentrations, calculated insulin resistance (HOMA-IR), body weight and body fat mass increased in all animals (time: all p's < 0.05); however, the increase in fasting glucose and HOMA-IR was significantly greater in subordinates than dominants (time x social status: p's < 0.05). Impaired glucose metabolism, (glucose > 100 mg/dl) incidence was significantly higher in subordinates (23%) than dominants (0%) (Fisher's exact test, p < 0.05). These findings suggest that chronic psychosocial stress, on a Western diet background, significantly increases type 2 diabetes risk in middle-aged female primates.

Effects of Combined Sertraline and Magnesium in Rat Atrium

The objective of this study is to determine the synergistic effects of an antioxidant ion Mg⁺², combined with selective serotonin reuptake inhibitor sertraline, in treatment or prevention of major depression and regulation of inotropic effect in the early postoperative period. Adult male 40 Wistar albino rats were randomly divided into 6 groups. Three to 4-mm long atrium strips were placed in organ bath, tension was adjusted to 2 g. Isometric contractions were induced with 10^-3 M adrenaline. Group 1 was the control group, cumulative sertraline was given to group 2, cumulative MgSO₄ to group 3, combined cumulative sertraline and MgSO₄ to group 4, intraperitoneal sertraline injection for 29 days to group 5, and intraperitoneal MgSO₄ injection for 14 days to group 6. Changes in weight, tensions, bleeding/clotting time, and biochemical findings were evaluated statistically. Isometric tension relationship between groups 1 and 3 was statistically significant after 4 mmol/L MgSO₄ (p < 0.05). A rapid inhibition of contraction was observed in group 4. Inhibition of spontaneous contractions of groups 5 and 6 was found to be statistically significant at close values, p < 0.05. When blood clotting times were compared, a statistically marked decrease was found in group 6, p < 0.05. Compared to control group, there was a significant decrease in blood lipids in group 4. While LDH and CK-MB increased from plasma enzymes in groups 5 and 6, no significant change was observed in NT-proBNP. Combined treatment of high dose MgSO₄ with antidepressants for pre or post-operative depression may cause fatal risks. Shortening clotting time may increase the risk of embolism and stroke. In order to reduce the risk of post-operative depression preoperatively, care should be taken when using magnesium combined with antidepressants and more studies are needed to be considered.

The negative effects of social bond disruption are partially ameliorated by sertraline administration in prairie voles

Negative social experiences influence both depression and cardiovascular dysfunction. Many individuals who experience negative mood states or cardiovascular conditions have limited social support. Therefore, investigation of drug treatments that may protect against the consequences of social stress will aid in designing effective treatment strategies. The current study used an animal model to evaluate the protective effect of sertraline administration on behavioral and cardiovascular consequences of social stress. Specifically, male prairie voles (Microtus ochrogaster), which are socially monogamous rodents that share several behavioral and physiological characteristics with humans, were isolated from a socially-bonded female partner, and treated with sertraline (16 mg/kg/day, ip) or vehicle during isolation. Unexpectedly, sertraline did not protect against depression-relevant behaviors, and it was associated with increased short- and long-term heart rate responses. However, sertraline administration improved heart rate variability recovery following a behavioral stressor, including increased parasympathetic regulation, and altered long-term neuronal activity in brain regions that modulate autonomic control and stress reactivity. These results indicate that sertraline may partially protect against the consequences of social stressors, and suggest a mechanism through which sertraline may beneficially influence neurobiological control of cardiac function.

Female Heart Health: Is GPER the Missing Link?

The G Protein-Coupled Estrogen Receptor (GPER) is a novel membrane-bound receptor that mediates non-genomic actions of the primary female sex hormone 17β-estradiol. Studies over the past two decades have elucidated the beneficial actions of this receptor in a number of cardiometabolic diseases. This review will focus specifically on the cardiac actions of GPER, since this receptor is expressed in cardiomyocytes as well as other cells within the heart and most likely contributes to estrogen-induced cardioprotection. Studies outlining the impact of GPER on diastolic function, mitochondrial function, left ventricular stiffness, calcium dynamics, cardiac inflammation, and aortic distensibility are discussed. In addition, recent data using genetic mouse models with global or cardiomyocyte-specific GPER gene deletion are highlighted. Since estrogen loss due to menopause in combination with chronological aging contributes to unique aspects of cardiac dysfunction in women, this receptor may provide novel therapeutic effects. While clinical studies are still required to fully understand the potential for pharmacological targeting of this receptor in postmenopausal women, this review will summarize the evidence gathered thus far on its likely beneficial effects.

Estradiol Treatment Initiated Early After Ovariectomy Regulates Myocardial Gene Expression and Inhibits Diastolic Dysfunction in Female Cynomolgus Monkeys: Potential Roles for Calcium Homeostasis and Extracellular Matrix Remodeling

Background Left ventricular ( LV ) diastolic dysfunction often precedes heart failure with preserved ejection fraction, the dominant form of heart failure in postmenopausal women. The objective of this study was to determine the effect of oral estradiol treatment initiated early after ovariectomy on LV function and myocardial gene expression in female cynomolgus macaques. Methods and Results Monkeys were ovariectomized and randomized to receive placebo (control) or oral estradiol at a human-equivalent dose of 1 mg/day for 8 months. Monkeys then underwent conventional and tissue Doppler imaging to assess cardiac function, followed by transcriptomic and histomorphometric analyses of LV myocardium. Age, body weight, blood pressure, and heart rate were similar between groups. Echocardiographic mitral early and late inflow velocities, mitral annular velocities, and mitral E deceleration slope were higher in estradiol monkeys (all P<0.05), despite similar estimated LV filling pressure. MCP1 (monocyte chemoattractant protein 1) and LV collagen staining were lower in estradiol animals ( P<0.05). Microarray analysis revealed differential myocardial expression of 40 genes (>1.2-fold change; false discovery rate, P<0.05) in estradiol animals relative to controls, which implicated pathways associated with better calcium ion homeostasis and muscle contraction and lower extracellular matrix deposition ( P<0.05). Conclusions Estradiol treatment initiated soon after ovariectomy resulted in enhanced LV diastolic function, and altered myocardial gene expression towards decreased extracellular matrix deposition, improved myocardial contraction, and calcium homeostasis, suggesting that estradiol directly or indirectly modulates the myocardial transcriptome to preserve cardiovascular function.

Long-term sertraline treatment and depression effects on carotid artery atherosclerosis in premenopausal female primates

OBJECTIVE

Atherosclerosis developed during premenopausal years predicts postmenopausal atherosclerosis burden. Selective serotonin reuptake inhibitor (SSRI) antidepressants, recently approved for hot flushes, have been associated with increased ischemic stroke risk in several observational studies; however, effects on carotid artery atherosclerosis, a strong predictor of future vascular events, are unknown.

METHODS

The effects of chronic administration of a commonly prescribed SSRI, sertraline HCl, on atherosclerosis in the carotid artery was assessed in a placebo-controlled, longitudinal, randomized study of premeonopausal depressed and nondepressed cynomolgus monkeys (Macaca fascicularis; n = 42). Physiologic and behavioral phenotypes were evaluated at baseline and after 18 months of oral sertraline (20 mg/kg, n = 21) or placebo (n = 21). Carotid artery atherosclerosis was measured post mortem via histomorphometry.

RESULTS

Atherosclerosis extent in the right common carotid artery, on average, was 60% greater in sertraline-treated depressed monkeys compared with all other groups (P = 0.028). The results of linear regression analyses suggested that sertraline and depression effects on atherosclerosis were not mediated by their effects on behavioral and physiological risk factors.

CONCLUSIONS

These findings suggest that chronic SSRI treatment is associated with the progression of carotid artery atherosclerosis, which may increase the risk for future vascular events, particularly in depressed women. The underlying mechanism remains to be determined, but does not appear to be related to SSRI effects on traditional cardiovascular risk factors.

Behavioral depression is associated with increased vagally mediated heart rate variability in adult female cynomolgus monkeys (Macaca fascicularis)

INTRODUCTION

Depressive symptoms (DS) in humans are associated with decreased resting state vagal activity, but sex seems to moderate this association. Recently, in human females DS have been associated with greater or similar cardiac vagal activity compared to men in both, clinical and non-clinical samples. A previously validated animal model of behavioral depression was used in the present study to investigate the association of DS and cardiac vagal activity in non-human primates.

METHODS

The root mean square of successive differences between adjacent heart beats (RMSSD) was used as an indicator of vagally-mediated heart rate variability in 24h heart rate recordings collected via telemetry in 42 adult female cynomolgus monkeys (Macaca fascicularis). Hierarchical regression models were used to estimate differences in RMSSD comparing monkeys with and without DS. To capture circadian variation patterns of RMSSD, additional quadratic, cubic and quartic terms of hour were added.

RESULTS

Monkeys showing behavioral DS had higher overall 24-h RMSSD. The interaction term of daytime with DS and polynomials of hour contributed significantly to the variance across models.

CONCLUSIONS

This is the first study investigating the association of DS and 24h cardiac vagal control in female non-human primates. Results replicate existing human studies showing higher cardiac vagal control in behavioral depressed vs. non-depressed female monkeys.

Sertraline inhibits increases in body fat and carbohydrate dysregulation in adult female cynomolgus monkeys

Selective serotonin reuptake inhibitor (SSRI) antidepressants are widely prescribed for depression and other disorders. SSRIs have become one of the most commonly used drugs in the United States, particularly by women. Acute effects on body composition and carbohydrate metabolism have been reported, but little is known regarding the effects of chronic SSRI use. We evaluated the effects of chronic administration of a commonly prescribed SSRI, sertraline HCl, on body weight and composition, fat distribution, carbohydrate metabolism, as well as activity, in adult female depressed and nondepressed cynomolgus monkeys (Macaca fascicularis; n=42) using a placebo-controlled, longitudinal, randomized study design. Phenotypes were evaluated prior to and after 18 months of oral sertraline (20mg/kg) or placebo. Over the 18 month treatment period, the placebo group experienced increases in body weight, body fat (visceral and subcutaneous) fasting insulin concentrations, and homeostasis model assessment of insulin resistance scores (HOMA-IR). Sertraline treatment prevented increases in body weight, fat, insulin, and HOMA-IR (all p<0.05), without significantly altering activity levels. Sertraline treatment altered adiponectin in an unusual way - reducing circulating adiponectin in depressed monkeys without affecting fat mass or body weight. Deleterious effects on adiponectin, a potentially insulin-sensitizing and atheroprotective protein, may result in adverse effects on cardiovascular health despite otherwise beneficial effects on body composition and carbohydrate metabolism.

Long term sertraline effects on neural structures in depressed and nondepressed adult female nonhuman primates

BACKGROUND

Selective serotonin reuptake inhibitors (SSRIs) are widely prescribed for mood and other disorders. However, their neural effects are difficult to study due to patient compliance and drug history variability, and rarely studied in those prescribed SSRIs for non-mood disorders. Here we evaluated SSRI effects on neural volumetrics in depressed and nondepressed monkeys.

METHODS

42 socially-housed cynomolgus monkeys were randomized to treatment balanced on pretreatment depressive behavior and body weight. Monkeys were trained for oral administration of placebo or 20 mg/kg sertraline HCl daily for 18 months and depressive and anxious behavior recorded. Volumes of neural regions of interest in depression were measured in magnetic resonance images and analyzed by 2 (depressed, nondepressed)×2 (placebo, sertraline) ANOVA.

RESULTS

Sertraline reduced anxiety (p=0.04) but not depressive behavior (p=0.43). Left Brodmann's Area (BA) 32 was smaller in depressed than nondepressed monkeys (main effect of depression: p<0.05). Sertraline and depression status interacted to affect volumes of left Anterior Cingulate Cortex (ACC), left BA24, right hippocampus (HC), and right anterior HC (sertraline×depression interactions: all p's<0.05). In the Placebo group, depressed monkeys had smaller right anterior HC and left ACC than nondepressed monkeys. In nondepressed monkeys, sertraline reduced right HC volume, especially right anterior HC volume. In depressed monkeys sertraline increased left ACC volume. In nondepressed monkeys, sertraline reduced left BA24 volumes resulting in smaller BA24 volumes in nondepressed than sertraline-treated depressed monkeys.

CONCLUSIONS

These observations suggest that SSRIs may differentially affect neural structures in depressed and nondepressed individuals.

Effects of long-term sertraline treatment and depression on coronary artery atherosclerosis in premenopausal female primates

OBJECTIVES

Major depressive disorder and coronary heart disease often co-occur in the same individuals. Selective serotonin reuptake inhibitors (SSRIs) are widely prescribed for depression and other disorders, but their effects on coronary heart disease risk remain unclear. We determined the effects of an SSRI on coronary artery atherosclerosis (CAA) in an established nonhuman primate model used to clarify the association between depression and CAA.

METHODS

Forty-two adult female cynomolgus macaques consuming a Western diet were characterized during an 18-month pretreatment phase and assigned to SSRI (sertraline hydrochloride 20 mg/kg, per os, once a day) or placebo balanced on pretreatment depression, body weight (BW), and iliac artery atherosclerosis extent measured via biopsy. After 18 months, CAA extent was measured using histomorphometry.

RESULTS

Before and during treatment, depressed monkeys had lower BW, body mass index, and plasma high-density lipoprotein cholesterol, and higher heart rates during the pretreatment (p < .01) but not the treatment phase (p = .17). There were no pretreatment differences between the sertraline and placebo groups. Sertraline reduced anxious behavior but had no effect on BW, body mass index, heart rate, plasma lipids, or depression. CAA, analyzed by a 2 (depressed, nondepressed) × 2 (placebo, sertraline) × 3 (coronary arteries) analysis of covariance adjusted for pretreatment iliac atherosclerosis, was greater in depressed than in nondepressed monkeys (p < .036), and in sertraline than in placebo-treated monkeys (p = .040). The observed CAA extent in depressed monkeys treated with sertraline was 4.9 times higher than that in untreated depressed monkeys, and 6.5 times higher than that in nondepressed monkeys, on average.

CONCLUSIONS

Depressed animals developed more CAA, and long-term treatment with sertraline resulted in more extensive CAA.

The effects of escitalopram on myocardial apoptosis and the expression of Bax and Bcl-2 during myocardial ischemia/reperfusion in a model of rats with depression

BACKGROUND

Major depressive disorder (MDD) is an independent risk factor for coronary heart disease (CHD), and influences the occurrence and prognosis of cardiovascular events. Although there is evidence that antidepressants may be cardioprotective after acute myocardial infarction (AMI) comorbid with MDD, the operative pathophysiological mechanisms remain unclear. Our aim was therefore to explore the molecular mechanisms of escitalopram on myocardial apoptosis and the expression of Bax and Bcl-2 in a rat model of depression during myocardial ischemia/reperfusion (I/R).

METHODS

Rats were divided randomly into 3 groups (n = 8): D group (depression), DI/R group (depression with myocardial I/R) and escitalopram + DI/R group. The rats in all three groups underwent the same chronic mild stress and separation for 21 days, at the same time, in the escitalopram + DI/R group, rats were administered escitalopram by gavage (10 mg/kg/day). Ligation of the rat's left anterior descending branch was done in the myocardial I/R model. Following which behavioral tests were done. The size of the myocardial infarction was detected using 1.5% TTC dye. The Tunel method was used to detect apoptotic myocardial cells, and both the Rt-PCR method and immunohistochemical techniques were used to detect the expression of Bcl-2 and Bax.

RESULTS

Compared with the D and DI/R groups, rats in Escitalopram + DI/R group showed significantly increased movements and sucrose consumption (P < .01). Compared with the DI/R group, the myocardial infarct size in the escitalopram + DI/R group was significantly decreased (P < .01). Compared with the D group, there were significantly increased apoptotic myocardial cells in the DI/R and escitalopram + DI/R groups (P < .01); however compared with the DI/R group, apoptotic myocardial cell numbers in the escitalopram + DI/R group were significantly decreased (P < .01). Compared with the DI/R group, there was a down-regulated Bax:Bcl-2 ratio in the escitalopram + DI/R group (P < .01).

CONCLUSIONS

These results suggest that in patients with AMI comorbid with MDD, there is an increase in pro-apoptotic pathways that is reversed by escitalopram. This suggests that clinically escitalopram may have a direct cardioprotective after acute myocardial infarction.