Behavioural signs of depression and apoptosis in the limbic system following myocardial infarction: effects of sertraline

Sertraline Pre-Treatment Attenuates Hemorrhagic Transformation Induced in Rats after Cerebral Ischemia Reperfusion via Down Regulation of Neuronal CD163: Involvement of M1/M2 Polarization Interchange and Inhibiting Autophagy

Cerebral ischemia reperfusion (I/R) is one of the neurovascular diseases which leads to severe brain deterioration. Haemorrhagic transformation (HT) is the main complication of ischemic stroke. It exacerbates by reperfusion, causing a more deleterious effect on the brain and death. The current study explored the protective effect of sertraline (Sert) against cerebral I/R in rats by inhibiting HT, together with the molecular pathways involved in this effect. Forty-eight wister male rats were divided into 4 groups: Sham, Sert + Sham, I/R, and Sert + I/R. The ischemic model was induced by bilateral occlusion of the common carotid artery for 20 min, then reperfusion for 24 h. Sertraline (20 mg/kg, p.o.) was administrated for 14 days before exposure to ischemia. Pre-treatment with Sert led to a significant attenuation of oxidative stress and inflammation. In addition, Sert attenuated phosphorylation of extracellular regulated kinases and nuclear factor kappa-p65 expression, consequently modulating microglial polarisation to M2 phenotype. Moreover, Sert prevented the hemorrhagic transformation of ischemic stroke as indicated by the notable decrease in neuronal expression of CD163, activity of Heme oxygenase-2 and matrix metalloproteinase-2 and 9 levels. In the same context, Sert decreased levels of autophagy and apoptotic markers. Furthermore, histological examination, Toluidine blue, and Prussian blue stain aligned with the results. In conclusion, Sert protected against cerebral I/R damage by attenuating oxidative stress, inflammation, autophagy, and apoptotic process. It is worth mentioning that our study was the first to show that Sert inhibited hemorrhagic transformation. The protective effect of sertraline against injury induced by cerebral ischemia reperfusion via inhibiting Hemorrhagic transformation.

Chaihujialonggumulitang shows psycho-cardiology therapeutic effect on acute myocardial infarction with comorbid anxiety by the activation of Nrf2/HO-1 pathway and suppression of oxidative stress and apoptosis

BACKGROUND

Anxiety is a common comorbidity of cardiovascular diseases, which deteriorated cardiac function. Chaihujialonggumulitang (BFG) was reported to have antioxidant properties, alleviate myocardial ischemia injury and improve anxiety-like behavior. The Nuclear factor erythroid 2-related factor 2 (Nrf2) /heme oxygenase-1 (HO-1) pathway is the main mechanism to defend against oxidative stress, and improve cardiac function. This study was to investigate the possible mechanism of BFG in the treatment of psycho-cardiology.

METHODS

AMI with comorbid anxiety rat model was established by ligation of the left anterior descending coronary artery combined with uncertain empty bottle stimulation, followed by the administration of BFG (1 mL/100 g/d by gavage) or Dimethyl fumarate (DMF, 10 mg/kg/d by intraperitoneal injection) for 6 days. Echocardiography, myocardial injury markers, H&E, and Masson staining were employed to evaluate cardiac function. Behavioral tests and hippocampus neurotransmitters were applied to record anxiety-like behavior. We employed immunohistochemistry, RT-PCR, western blotting, and biochemical analysis to detect the protein and gene expression of Nrf2/HO-1 pathway-related factors, and oxidative stress and apoptosis parameters.

RESULTS

Rats in the AMI and complex groups showed cardiac function deterioration, as well as anxiety-like behavior. BFG improved echocardiography indicators, reduced myocardial injury markers, and attenuated myocardial pathological changes. BFG also ameliorated anxiety-like behaviors and elevated neurotransmitters levels. BFG promoted the activation of Nrf2/HO-1 pathway, increased antioxidant enzyme activities, reduced lipid peroxidation levels, and alleviated oxidative damage and apoptosis. DMF showed therapeutic effects and molecular mechanisms similar to BFG.

CONCLUSION

BFG may possess a psycho-cardiology therapeutic effect on AMI with comorbid anxiety by the activation of the Nrf2/HO-1 pathway and suppression of oxidative stress and apoptosis.

Downregulation of interleukin-1 beta via Jmjd3 inhibition improves post-myocardial infarction depression

BACKGROUND

Patients with myocardial infarction (MI) comorbid with the depressive disorder may have increased serum cytokine concentrations, notably, of interleukin-1 beta (IL-1β). The histone H3 lysine-27 (H3K27) demethylase Jmjd3 is crucial in cytokine regulation, and administering an H3K27 demethylase-selective inhibitor (GSK J4) might ameliorate inflammatory symptoms. We hypothesized that Jmjd3 might regulate IL-1β concentrations, thus affecting the development of post-MI depression (PMD). In this study, a mouse model was created to examine the connection between IL-1β and PMD and determine the regulatory function of cytokine in controlling inflammation and depressive symptoms.

METHODS

MI was induced in 30 5-week-old male C57BL/6N mice via a left coronary ligation, and MI onset was confirmed by electrocardiogram (ECG). After treatment with dimethylsulfoxide (DMSO) or GSK J4 for 14 days, the mice were subjected to tail-suspension tests (TSTs) and forced swimming tests (FSTs) before being sacrificed for tissue harvest.

RESULTS

In the TSTs, the GSK J4-treated MI mice displayed a significantly shorter immobility time than did the DMSO-treated MI mice (P<0.001). In the FSTs, the DMSO-treated MI mice showed a significantly longer immobility time than did the DMSO-treated sham-operated mice (P<0.001). The GSK J4-treated MI mice had a significantly reduced immobility time compared to the DMSO-treated MI mice (P<0.001). IL-1β expression in the myocardium, hippocampus, prefrontal cortex (PFC), and hypothalamus increased after MI onset (P=0.003, 0.015, 0.0003, and 0.013, respectively) but decreased after treatment with GSK J4 (P<0.001, P=0.005, P<0.001, P=0.018, respectively). In the myocardium and hypothalamus, Jmjd3 expression levels were lower in mice that received GSK J4 treatment than in those that received DMSO treatment (P<0.05).

CONCLUSIONS

GSK J4 inhibited the cardiac expression of IL-1β and Jmjd3, and alleviated PMD in MI mice. Therefore, IL-1β and Jmjd3 may be critical in the pathogenesis of PMD, and Jmjd3 may potentially serve as a target for PMD treatment.

Lycopene and Chrysin through Mitigation of Neuroinflammation and Oxidative Stress Exerted Antidepressant Effects in Clonidine-Induced Depression-like Behavior in Rats

Depression is a severely debilitating psychiatric disorder that influences more than 15% of the population worldwide. It has been demonstrated that it is associated with a high risk of developing other diseases such as cardiovascular diseases, diabetes, stroke, epilepsy, and cancer. The current study examines the possibility of chrysin and lycopene having an antidepressant effect in a rat model of depression induced by clonidine, as well as the mechanisms underlying this effect, including the role of neuroinflammation and oxidative stress. Rats were allotted into seven groups. The rats in group 1 served as a control. Group 2 received lycopene only. Group 3 was provided chrysin only. Group 4 was administered clonidine and served as the model. Group 5 was offered lycopene and clonidine. Group 6 was administered chrysin and clonidine. Group 7 was given FLX and clonidine and represented the standard. The experiment lasted two weeks, during which behavioral, biochemical, histopathological, and immunohistochemical measurements were performed. Lycopene and chrysin were used to correct the concentrations of noradrenaline and serotonin hippocampal tissue concentrations. These findings were also improved by immunohistochemical analysis of GFAP, VEGF, caspase3, and histopathological examinations, in which pretreatment of rats with lycopene and chrysin reversed all clonidine-induced alterations. The current research demonstrates that lycopene and chrysin have an auspicious antidepressant effect against clonidine that provoked behavioral hopelessness in rats. Manipulating oxidative stress, inflammation, and apoptosis may partially represent the corrective mechanism for the neuroprotective actions against the depressive effect of clonidine.

Effect of m-Trifluoromethyl-diphenyl diselenide on the Pain-Depression Dyad Induced by Reserpine: Insights on Oxidative Stress, Apoptotic, and Glucocorticoid Receptor Modulation

Chronic pain and depression often coexist sharing common pathological mechanisms, and available analgesics and antidepressants have demonstrated limited clinical efficacy. Evidence has demonstrated that neuronal oxidative stress, apoptosis, and also glucocorticoid receptor dysregulation facilitate the occurrence and development of both chronic pain and depression. This study evaluated the effect of the organoselenium compound m-trifluoromethyl-diphenyl diselenide [(m-CF₃-PhSe)₂] in the pain-depression comorbidity induced by reserpine. Mice were treated with reserpine 0.5 mg/kg for 3 days (intraperitoneal, once a day), and in the next 2 days, they were treated with (m-CF₃-PhSe)₂ 10 mg/kg (intragastric, once a day). Thirty minutes after the last administration of (m-CF₃-PhSe)₂, mice were subjected to the behavioral testing. (m-CF₃-PhSe)₂ treatment reverted the reserpine-increased thermal hyperalgesia and depressive-like behavior observed in the hot-plate test and forced swimming test, respectively. Reserpine provoked a decrease of crossings and rearings in the open-field test, while (m-CF₃-PhSe)₂ presented a tendency to normalize these parameters. Reserpine and/or (m-CF₃-PhSe)₂ treatments did not alter the locomotor activity of mice observed in the rota-rod test. These effects could be related to modulation of oxidative stress, apoptotic pathway, and glucocorticoid receptors, once (m-CF₃-PhSe)₂ normalized thiobarbituric acid reactive substances and 4-hydroxynonenal modified protein levels, markers of lipoperoxidation, poly(ADP-ribose) polymerase cleaved/total ratio, and glucocorticoid receptor levels increased by reserpine in the hippocampus. Considering that pain-depression dyad is a complex state of difficult treatment, this organoselenium compound could raise as an interesting alternative to treat pain-depression condition.

Cognitive impairment in myocardial infarction and heart failure

Myocardial infarction (MI) occurs when coronary blood flow is decreased due to an obstruction/occlusion of the vessels, leading to myocardial death and progression to heart failure (HF). Cognitive impairment, anxiety, depression and memory loss are the most frequent mental health problems among patients with HF. The most common cause of cognitive decline is cardiac systolic dysfunction, which leads to reduced cerebral perfusion. Several in vivo and clinical studies provide information regarding the underlying mechanisms of HF in brain pathology. Neurohormonal activation, oxidative stress, inflammation, glial activation, dendritic spine loss and brain programmed cell death are all proposed as contributors of cognitive impairment in HF. Furthermore, several investigations into the effects of various medications on brain pathology utilizing MI models have been reported. In this review, potential mechanisms involving HF-associated cognitive impairment, as well as neuroprotective interventions in HF models, are discussed and summarized. In addition, gaps in the surrounding knowledge, including the types of brain cell death and the effects of cell death inhibitors in HF, are presented and discussed. This review provides valuable information that will suggest the potential therapeutic strategies for cognitive impairment in patients with HF.

Ghrelin attenuates depressive-like behavior, heart failure, and neuroinflammation in postmyocardial infarction rat model

Depression after myocardial infarction (MI) and chronic heart failure (CHF) is a common condition that is resistant to anti-depressive drugs. Ghrelin (a peptide hormone) shows dual protective effects on heart and brain. Whether ghrelin treatment attenuated depression after MI was investigated. Coronary artery occlusion was performed to induce MI and subsequent CHF in rats. Ghrelin (100 μg/kg in 0.5 ml of saline) or vehicle (0.5 ml of saline) was injected subcutaneously twice a day for 4 weeks. At week 5, all the animals underwent behavioral assessments including sucrose preference test (SPT), elevated plus maze test (EPM), and open field test (OFT). After cardiac function analysis, brain tissues were processed to determine inflammatory cytokines and microglial activations in hippocampus. Results showed that ghrelin substantially improved cardiac dysfunction, infarction size, and cardiac remodeling and modulated the release of inflammatory cytokines and the increase of Iba-1 positive microglia and glial fibrillary acidic protein-positive astrocytes in the CA1 area of hippocampus. Behavioral tests revealed that this treatment remarkably increased sucrose preference and mobile times and numbers. These findings provided evidence that peripheral ghrelin administration inhibits depression-like behavior and neuroinflammation and thus could be a new approach for the treatment of CHF-associated depression.

Novel therapeutic targets in mood disorders: Pentoxifylline (PTX) as a candidate treatment

Numerous pharmacological treatments for mood disorders are currently available; however, rates of treatment resistance, relapse and recurrence remain high. Therefore, novel treatments acting outside of the conventionally targeted monoamine system are urgently needed to improve patient outcomes. Emerging and converging evidence suggests that immune dysfunction, oxidative stress, impaired cerebral blood flow (CBF) and decreased neurotrophic factors all contribute to mood disorder pathophysiology and are therefore treatment targets of interest. Pentoxifylline (PTX) is a phosphodiesterase inhibitor with potent anti-inflammatory and antioxidant effects, with additional pleiotropic effects that lead to improved CBF and increases in brain derived neurotrophic factor (BDNF) levels. The direct effect of non-specific phosphodiesterase inhibition may also improve alertness and cognitive function through enhancing second messenger systems. Replicated preclinical studies have demonstrated antidepressant-like effects in animal models. Small preliminary clinical trials have demonstrated promising results for antidepressant and procognitive effects, however, have yet to be replicated in larger mood disorder samples. Only one randomized clinical trial (RCT) specifically assessed the effects of adjunctive PTX in major depressive disorder (MDD), showing clinically and statistically significant antidepressant effects compared to placebo. No studies have assessed PTX in bipolar disorder (BD), where inflammation and altered CBF have also been strongly implicated. Taken together, PTX presents as a promising pleiotropic agent with several potential novel mechanisms of action meriting further evaluation in clinical trials to evaluate target engagement, antidepressant, procognitive and mood stabilizing effects.

Protective effect of epigallocatechin-3-gallate against neuroinflammation and anxiety-like behavior in a rat model of myocardial infarction

OBJECTIVE

Individuals who experience myocardial infarction (MI) often experience anxiety. Green tea has potent antioxidative properties and, epigallocatechin-3-gallate (EGCG), which is a primary component of tea polyphenols, has advantageous effects on anxiety and depression. However, its mechanism of action regarding the inhibition of anxiety-like symptoms after MI remains unclear. This study examined whether EGCG alleviated anxiety-like behavior in MI rats and its possible mechanism.

MATERIAL AND METHODS

Rats were administered a daily gavage of EGCG (50 mg/kg) 7 days before and 14 consecutive days after the MI procedure. The open-field test and light/dark shuttle box were performed to evaluate anxiety-like behavior. Serum and hippocampus interleukin (IL)-6 levels were tested using ELISA. Caspase 3, caspase 8, caspase 9 and bcl-2 messenger RNA levels in the hippocampus were determined using quantitative polymerase chain reaction, and STAT3 protein was detected by Western blot.

RESULTS

Results of the open field test and light/dark shuttle box task demonstrated that the MI procedure induced anxiety-like behavior in the animals, and this impairment was improved by EGCG. Daily EGCG administration significantly decreased the level of IL-6 both in serum and hippocampus after MI. The administration of EGCG also significantly moderated the expression of caspases 3, 8, and 9 mRNA, which was related to apoptosis in the hippocampus. Furthermore, EGCG also downregulated the expression of STAT3, which was related to the activity of IL-6. These results suggest that EGCG alleviated anxiety-like behavior by inhibiting increases in neuroinflammation and apoptosis in the rat hippocampus. In addition, EGCG reversed alterations of IL-6 and STAT3 in the brain to alleviate apoptosis in the hippocampus.

CONCLUSIONS

Thus, EGCG reversed anxiety-like behavior through an anti-inflammation effect to alleviate apoptosis in neurons and may be a useful therapeutic material for anxiety-like behavior after MI.

Alterations of medial prefrontal cortex bioelectrical activity in experimental model of isoprenaline-induced myocardial infarction

BACKGROUND

Clinical and animal studies have found that anxiety and depression are significantly more common after acute myocardial infarction (AMI). The medial prefrontal cortex (PFC) has a dual role: in higher brain functions and in cardiovascular control, making it a logical candidate for explaining the perceived bidirectional heart-brain connection. We used parallel Electrocardiography (ECG) and Electrocorticography (ECoG) registration to investigate AMI-induced changes in medial PFC bioelectrical activity in a rat model of AMI.

MATERIALS AND METHODS

Adult male Wistar albino rats were used in the study. Gold-plated recording electrodes were implanted over the frontal cortex for ECoG recording. ECG was recorded via two holter electrodes attached on the skin of the back fixed in place by a jacket. Induction of AMI was performed by isoprenaline (150 mg/kg, i.p.). ECoG and ECG signals were registered at baseline, during 3 hours after isoprenaline administration and at 24 hours after isoprenaline administration.

RESULTS

Significant increases of theta, alpha, and beta electroencephalographic (EEG) band power were observed in different time intervals after isoprenaline administration. Significant increase of theta band peak frequency was also observed during the first hour after isoprenaline administration. No statistically significant differences in band-power activity were found between the pre-isoprenaline measurements and 24 hours after administration.

CONCLUSION

Our results demonstrate significant increases in EEG band power of alpha beta and theta bands during isoprenaline-induced AMI model. These are the first findings to connect heart damage during isoprenaline- induced AMI to disturbances in the cortical bioelectrical activity.

Inhibition of inflammation by minocycline improves heart failure and depression-like behaviour in rats after myocardial infarction

Rationale

Patients with heart failure have an increased incidence of depression. Central and peripheral inflammation play a major role in the pathophysiology of both heart failure and depression.

Aim

Minocycline is an antibiotic that inhibits microglia activation and release of pro-inflammatory cytokines. We assessed effects of minocycline on extent of heart failure and depression at 2 and 8 weeks post myocardial infarction.

Methods/Results

Male Wistar rats were randomly divided into 3 groups: (i) sham + vehicle; (ii) MI + vehicle; and (iii) MI + minocycline with n/group of 8, 9 and 9 at 2 weeks, and 10, 16, 8 at weeks, respectively. Oral minocycline (50 mg/kg/day) or vehicle started 2 days before surgery. Depression-like behaviour was assessed with sucrose preference and forced swim tests, and cardiac function with echo and hemodynamics. After myocardial infarction, microglia activation and plasma/brain pro-inflammatory cytokines increased, which were mostly prevented by minocycline. At 8 weeks, cardiac dysfunction was attenuated by minocycline: infarct size (MI + Vehicle 29±1, MI + Min 23±1%), ejection fraction (Sham 80±1, MI + Vehicle 48±2, MI + Min 58±2%) and end diastolic pressure (Sham 3.2±0.3, MI + Vehicle 18.2±1.1, MI + Min 8.5±0.9 mm Hg). Depression-like behaviour was significantly improved by minocycline in sucrose preference test (% Sucrose Intake: Sham 96±1, MI + Vehicle 78±2, MI + Min 87±2) and forced swim test (% Immobile: Sham 40±4, MI + Vehicle 61±3, MI + Min 37±6).

Conclusion

Rats post myocardial infarction develop systemic inflammation, heart failure and depression-like behaviour that are all attenuated by minocycline. Targeting (neuro) inflammation may represent new therapeutic strategy for patients with heart failure and depression.

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.

Learned helplessness reveals a population at risk for depressive-like behaviour after myocardial infarction in mice

Aims

Myocardial infarction (MI) and heart failure (HF) are risk factors for the development of depression, additionally worsening the quality of life and patient outcome. How HF causes depression and how depression promotes HF remain mechanistically unclear, which is at least partly caused by the difficulty of in vivo modelling of psychosomatic co‐morbidity. We aimed to study the potential sequence of events with respect to different depression aspects upon HF.

Methods and results

Male C57BL6 mice underwent MI, followed by behavioural and echocardiographic characterization. Motility, exploration, and anxiety‐like behaviour were unaffected in mice after MI. We did not observe increased depressive‐like behaviour in the sucrose preference, tail suspension, or Porsolt forced swim test. Mice did not display signs of learned helplessness (LH) when compared to sham. Accordingly, cluster analysis revealed only a slightly higher quota of LH in HF (38%) vs. sham mice (32%). But strikingly, three‐group cluster analysis revealed an additional intermediate subpopulation at risk for LH after HF (29%). Interestingly, this population featured elevated cardiac expression of nr4a1.

Conclusions

The LH paradigm uncovered a subtle predisposition to depressive‐like behaviour after MI, whereas testing for anhedonia and despair was insufficient to show a behavioural shift in mice. Therefore, we suggest an accumulating risk profile and a multiple‐hits hypothesis regarding the pathogenesis of co‐morbid depression after MI. Symptoms of LH may present a marker of subclinical depression after MI, the impact of which remains to be investigated. The proposed sequence of behavioural testing enables the mechanistic dissection of cardio‐psychogenic signalling in the future.

Inflammation associated with chronic heart failure leads to enhanced susceptibility to depression

Epidemiological and clinicopathological studies indicate that there is a high risk for chronic heart failure (CHF) in patients suffering from neuropsychiatric disorders, such as depression. However, it is unclear whether CHF causes depression, and the underlying mechanisms of this association remain largely unknown. In this study, mice with myocardial infarction and CHF were used to investigate behavioral alterations as well as changes in the brain-heart axis. During the first 6 months, abnormalities in neuropsychiatric behaviors were detected in mice with CHF. Using the sucrose preference test, a 9 months course of CHF resulted in two subgroups: mice with a significant decrease in sucrose preference, defined herein as "susceptible" (Sus), and mice with a normal sucrose preference, defined herein as "resilient." Compared to the resilient and sham-operated animals, the Sus mice displayed imbalances in glutamate transmission and hypothalamic-pituitary-adrenal axis activation, abnormal synaptic plasticity, and increased inflammatory responses. Furthermore, abnormal kynurenine metabolism was detected in Sus mice. Our results suggest that long-term CHF increases inflammatory responses in the central nervous system and leads to depression in Sus mice.

Cognitive Deficits Following a Post-Myocardial Infarct in the Rat Are Blocked by the Serotonin-Norepinephrine Reuptake Inhibitor Desvenlafaxine

Myocardial infarction (MI) in animal models induces cognitive deficits as well as the activation of caspase in the limbic system; both can be blocked by 2 weeks of treatment following MI using tricyclic antidepressants or selective serotonin uptake blockers. Here we used three different treatment schedules to test the short- and long-term effects of the combined serotonin-norepinephrine reuptake inhibitor desvenlafaxine on post-MI-associated cognitive deficits and caspase activation. MI was induced in 39 young adult rats, and 39 rats served as sham-operated controls. Desvenlafaxine (3 mg/kg/day, i.p.) or saline was administered according to one of three schedules: (1) for 2 weeks, starting right after surgery; (2) for 16 weeks, starting 2 weeks after surgery; (3) for 16 weeks, starting right after surgery. Behavior was tested 2 weeks (social interaction, passive avoidance) and 16 weeks (forced swimming, Morris water maze) after surgery. Caspase-3 and caspase-6 activities were measured 16 weeks after surgery. At 2 and 16 weeks post-surgery, saline-treated MI rats displayed performance deficits compared to desvenlafaxine-treated rats, regardless of the treatment schedule. Caspase-3 activity was higher in the amygdala (medial and lateral) and hippocampal CA3 region in untreated MI rats, whereas caspase-6 activity was higher in the CA1 region. Caspase-6 activity correlated positively with deficits in the Morris water maze. These results indicate that, independently of treatment schedules, various treatment schedules with desvenlafaxine can prevent MI-associated cognitive deficits and decrease caspase activities in the limbic system.

Sex differences in depression-like behavior and neuroinflammation in rats post-MI: role of estrogens

Patients with heart failure (HF) have a high prevalence of depression associated with a worse prognosis, particularly in older women. The present study evaluated whether sex and estrogens affect depression-like behavior and associated neuroinflammation induced by myocardial infarction (MI) in rats. MI was induced by occlusion of the left anterior descending artery in young adult male and female Wistar rats or in ovariectomized (OVX) female rats without and with estrogen [17β-estradiol (E₂)] replacement. MI groups showed a comparable degree of cardiac dysfunction. Eight weeks post-MI, male rats with HF exhibited depression-like behaviors, including anhedonia and higher immobility in the sucrose preference and forced swim tests, which were not observed in female rats with HF. In the cued fear conditioning test, male but not female rats with HF froze more than sham rats. After OVX, female sham rats developed mild depression-like behaviors that were pronounced in OVX female rats post-MI and were largely prevented by E₂ replacement. Cytokine levels in the plasma and paraventricular nucleus increased in both sexes with HF, but only male rats with HF showed an increase in cytokine levels in the prefrontal cortex. OVX alone did not affect cytokine levels, but OVX-MI caused significant increases in the prefrontal cortex, which were shifted to an anti-inflammatory pattern by E₂ replacement. These results suggest that estrogens prevent depression-like behavior induced by HF post-MI in young adult female rats by inhibiting proinflammatory cytokine production and actions in the prefrontal cortex. NEW & NOTEWORTHY In contrast to male rats, female rats with heart failure after myocardial infarction do not develop depression-like behavior or increases in prefrontal cortex cytokines. However, after ovariectomy, female rats exhibit similar changes, which are prevented by 17β-estradiol replacement. Neuroinflammation in the prefrontal cortex in male subjects may contribute to depression-like behavior, whereas its estrogen-dependent absence in female subjects may protect against depression.

Electroacupuncture Improved the Function of Myocardial Ischemia Involved in the Hippocampus-Paraventricular Nucleus-Sympathetic Nerve Pathway

We investigated the hippocampus-paraventricular nucleus- (PVN-) sympathetic nerve pathway in electroacupuncture (EA) at the heart meridian for the treatment of myocardial ischemia by observing PVN neuronal discharge, sympathetic nerve discharge, and hemodynamics parameters. Sprague Dawley (SD) rats were equally divided into four groups: Sham, Model, Model + EA, and Model + EA + Lesion. The model rat was established by ligating the left anterior descending branch of the coronary artery. Changes in the sympathetic nerve discharge and hemodynamic parameters were observed. The Model + EA exhibited a significantly lower discharge frequency of PVN neurons compared with the Model. The Model + EA + Lesion had a significantly higher discharge frequency compared with the Model + EA. The total discharge frequency of PVN neurons and interneurons were positively correlated with the sympathetic nerve discharge. The total discharge frequency of PVN neurons was positively correlated with heart rate (HR) and negatively correlated with mean arterial pressure (MAP) and rate pressure product (RPP). The discharge frequency of interneurons was positively correlated with HR and negatively correlated with MAP and RPP. The hippocampus-PVN-sympathetic nerve pathway is involved in electroacupuncture at the heart meridian and interneurons are the key neurons in PVNs.

Psychological sequelae of myocardial infarction

Patient with myocardial infarction (MI) are often affected by psychological disorders such as depression, anxiety, and post-traumatic stress disorder. Psychological disorders are disabling and have a negative influence on recovery, reduce the quality of life and causes high mortality rate in MI patients. Despite tremendous advancement in technologies, screening scales, and treatment strategies, psychological sequelae of MI are currently understudied, underestimated, underdiagnosed, and undertreated. Depression is highly prevalent in MI patients followed by anxiety and post-traumatic stress disorder. Pathophysiological factors involved in psychopathologies observed in patients with MI are sympathetic over-activity, hypothalamic-pituitary-adrenal axis dysfunction, and inflammation. Numerous preclinical and clinical studies evidenced a positive association between MI and psychopathologies with a common molecular pathophysiology. This review provides an update on diagnostic feature, prevalence, pathophysiology, clinical outcomes, and management strategies of psychopathologies associated with MI. Moreover, preclinical research findings on molecular mechanisms involved in post-MI psychopathologies and future therapeutic strategies have been outlined in the review.

Pathogenesis of depression- and anxiety-like behavior in an animal model of hypertrophic cardiomyopathy

Cardiovascular dysfunction is highly comorbid with mood disorders, such as anxiety and depression. However, the mechanisms linking cardiovascular dysfunction with the core behavioral features of mood disorder remain poorly understood. In this study, we used mice bearing a knock-in sarcomeric mutation, which is exhibited in human hypertrophic cardiomyopathy (HCM), to investigate the influence of HCM over the development of anxiety and depression. We employed behavioral, MRI, and biochemical techniques in young (3-4 mo) and aged adult (7-8 mo) female mice to examine the effects of HCM on the development of anxiety- and depression-like behaviors. We focused on females because in both humans and rodents, they experience a 2-fold increase in mood disorder prevalence vs. males. Our results showed that young and aged HCM mice displayed echocardiographic characteristics of the heart disease condition, yet only aged HCM females displayed anxiety- and depression-like behaviors. Electrocardiographic parameters of sympathetic nervous system activation were increased in aged HCM females vs. controls and correlated with mood disorder-related symptoms. In addition, when compared with controls, aged HCM females exhibited adrenal gland hypertrophy, reduced volume in mood-related brain regions, and reduced hippocampal signaling proteins, such as brain-derived neurotrophic factor and its downstream targets vs. controls. In conclusion, prolonged systemic HCM stress can lead to development of mood disorders, possibly through inducing structural and functional brain changes, and thus, mood disorders in patients with heart disease should not be considered solely a psychologic or situational condition.-Dossat, A. M., Sanchez-Gonzalez, M. A., Koutnik, A. P., Leitner, S., Ruiz, E. L., Griffin, B., Rosenberg, J. T., Grant, S. C., Fincham, F. D., Pinto, J. R. Kabbaj, M. Pathogenesis of depression- and anxiety-like behavior in an animal model of hypertrophic cardiomyopathy.

Early citalopram treatment increases mortality due to left ventricular rupture in mice after myocardial infarction

AIMS

Both anxiety and depression are common and independent outcome predictors in patients after myocardial infarction (MI). However, it is unclear whether and how anti-depressants influence remodeling after MI. Thus, we studied cardiac remodeling in mice after experimental MI under treatment with citalopram, a selective serotonin reuptake inhibitor widely used as antidepressant.

METHODS AND RESULTS

Treatment with citalopram versus saline was applied via osmotic pump after coronary artery ligation. Two different groups were studied: early treatment during the healing phase (starting immediately after surgery), or late treatment in the remodeling phase (starting 7days after surgery). Late treatment did not change mortality or left ventricular remodeling after MI over the period of 6weeks. However, in the early treatment group mortality was increased in citalopram-treated mice predominantly due to left ventricle rupture without differences in infarct size. Remodeling 4weeks after MI was not altered by the treatment. Neither infiltration of inflammatory cells, as determined by FACS analysis of myocardial tissue, nor mRNA-expression of inflammatory cytokines changed 3days after MI in the early treatment group. However, extracellular matrix functioning was altered: There was a significant increase of MMP13 in citalopram treated animals after MI. Pretreatment with the MMP inhibitor PD 166793 prevented left ventricular ruptures and demonstrated a tendency to improved survival after citalopram treatment.

CONCLUSIONS

Treatment with antidepressant citalopram in the acute but not in the late phase after MI significantly increased mortality in mice by disturbing early healing. Pharmacological MMP inhibition partially reversed the deleterious effects of citalopram.

Caspase-3 Activity in the Rat Amygdala Measured by Spectrofluorometry After Myocardial Infarction

Myocardial infarction (MI) has dramatic mid- and long-term consequences at the physiological and behavioral levels, but the mechanisms involved are still unclear. Our laboratory has developed a rat model of post-MI syndrome that displays impaired cardiac functions, neuronal loss in the limbic system, cognitive deficits and behavioral signs of depression. At the neuronal level, caspase-3 activation mediates post-MI apoptosis in different limbic regions, such as the amygdala – peaking at 3 days post-MI. Cognitive and behavioral impairments appear 2-3 weeks post-MI and these correlate statistically with measures of caspase-3 activity. The protocol described here is used to induce MI, collect amygdala tissue and measure caspase-3 activity using spectrofluorometry. To induce MI, the descending coronary artery is occluded for 40 min. The protocol for evaluation of caspase-3 activation starts 3 days after MI: the rats are sacrificed and the amygdala isolated rapidly from the brain. Samples are quickly frozen in liquid nitrogen and kept at -80 °C until actual analysis. The technique performed to assess caspase-3 activation is based on cleavage of a substrate (DEVD-AMC) by caspase-3, which releases a fluorogenic compound that can be measured by spectrofluorometry. The methodology is quantitative and reproducible but the equipment required is expensive and the procedure for quantifying the samples is time-consuming. This technique can be applied to other tissues, such as the heart and kidneys. DEVD-AMC can be replaced by other substrates to measure the activity of other caspases.

Vagotomy prevents the effect of probiotics on caspase activity in a model of postmyocardial infarction depression

BACKGROUND

Myocardial infarction (MI) is associated with apoptosis in the amygdala and, ultimately, with clinical signs of depression. Different treatments have proven to be beneficial in preventing depression, including combination of the probiotics Lactobacillus helveticus and Bifidobacterium longum for prophylaxis. We have speculated previously that the benefit of these probiotics is due to their anti-inflammatory properties, and evidence suggests that an intact vagus nerve is important for this effect to occur. This study was designed to ascertain vagus nerve involvement in the beneficial influence of probiotics on caspase activities in our post-MI animal model of depression.

METHODS

Probiotics and/or vehicle were administered daily to male adult rats, 14 days before MI and until euthanasia. Vagotomy was performed in subgroups of rats 40 min before MI. They were sacrificed after 3 days of reperfusion, and MI size was assessed along with caspase-3 and -8 activities in the amygdala.

KEY RESULTS

Probiotics had no effect on infarct size but vagotomy increased it. Caspase-3 and caspase-8 activities in the amygdala were higher in MI than in sham-operated rats, and this outcome was reversed by probiotics. The beneficial influence of probiotics was abolished by vagotomy.

CONCLUSIONS & INFERENCES

Our data indicate that the effect of probiotics on caspase activities in the amygdala after MI depends on an intact vagus nerve.

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.

Resolvin D1, a metabolite of omega-3 polyunsaturated fatty acid, decreases post-myocardial infarct depression

We hypothesized that inflammation induced by myocardial ischemia plays a central role in depression-like behavior after myocardial infarction (MI). Several experimental approaches that reduce inflammation also result in attenuation of depressive symptoms. We have demonstrated that Resolvin D1 (RvD1), a metabolite of omega-3 polyunsaturated fatty acids (PUFA) derived from docosahexaenoic acid, diminishes infarct size and neutrophil accumulation in the ischemic myocardium. The aim of this study is to determine if a single RvD1 injection could alleviate depressive symptoms in a rat model of MI. MI was induced in rats by occlusion of the left anterior descending coronary artery for 40 min. Five minutes before ischemia or after reperfusion, 0.1 μg of RvD1 or vehicle was injected in the left ventricle cavity. Fourteen days after MI, behavioral tests (forced swim test and socialization) were conducted to evaluate depression-like symptoms. RvD1 reduced infarct size in the treated vs. the vehicle group. Animals receiving RvD1 also showed better performance in the forced swim and social interaction tests vs. vehicle controls. These results indicate that a single RvD1 dose, given 5 min before occlusion or 5 min after the onset of reperfusion, decreases infarct size and attenuates depression-like symptoms.

Experimental heart failure causes depression-like behavior together with differential regulation of inflammatory and structural genes in the brain

BACKGROUND

Depression and anxiety are common and independent outcome predictors in patients with chronic heart failure (CHF). However, it is unclear whether CHF causes depression. Thus, we investigated whether mice develop anxiety- and depression-like behavior after induction of ischemic CHF by myocardial infarction (MI).

METHODS AND RESULTS

In order to assess depression-like behavior, anhedonia was investigated by repeatedly testing sucrose preference for 8 weeks after coronary artery ligation or sham operation. Mice with large MI and increased left ventricular dimensions on echocardiography (termed CHF mice) showed reduced preference for sucrose, indicating depression-like behavior. 6 weeks after MI, mice were tested for exploratory activity, anxiety-like behavior and cognitive function using the elevated plus maze (EPM), light-dark box (LDB), open field (OF), and object recognition (OR) tests. In the EPM and OF, CHF mice exhibited diminished exploratory behavior and motivation despite similar movement capability. In the OR, CHF mice had reduced preference for novelty and impaired short-term memory. On histology, CHF mice had unaltered overall cerebral morphology. However, analysis of gene expression by RNA-sequencing in prefrontal cortical, hippocampal, and left ventricular tissue revealed changes in genes related to inflammation and cofactors of neuronal signal transduction in CHF mice, with Nr4a1 being dysregulated both in prefrontal cortex and myocardium after MI.

CONCLUSIONS

After induction of ischemic CHF, mice exhibited anhedonic behavior, decreased exploratory activity and interest in novelty, and cognitive impairment. Thus, ischemic CHF leads to distinct behavioral changes in mice analogous to symptoms observed in humans with CHF and comorbid depression.

Electroacupuncture promotes proliferation of amplifying neural progenitors and preserves quiescent neural progenitors from apoptosis to alleviate depressive-like and anxiety-like behaviours

The present study was designed to investigate the effects of electroacupuncture (EA) on depressive-like and anxiety-like behaviours and neural progenitors in the hippocampal dentate gyrus (DG) in a chronic unpredictable stress (CUS) rat model of depression. After being exposed to a CUS procedure for 2 weeks, rats were subjected to EA treatment, which was performed on acupoints Du-20 (Bai-Hui) and GB-34 (Yang-Ling-Quan), once every other day for 15 consecutive days (including 8 treatments), with each treatment lasting for 30 min. The behavioural tests (i.e., forced swimming test, elevated plus-maze test, and open-field entries test) revealed that EA alleviated the depressive-like and anxiety-like behaviours of the stressed rats. Immunohistochemical results showed that proliferative cells (BrdU-positive) in the EA group were significantly larger in number compared with the Model group. Further, the results showed that EA significantly promoted the proliferation of amplifying neural progenitors (ANPs) and simultaneously inhibited the apoptosis of quiescent neural progenitors (QNPs). In a word, the mechanism underlying the antidepressant-like effects of EA is associated with enhancement of ANPs proliferation and preserving QNPs from apoptosis.

The effects of apoptosis vulnerability markers on the myocardium in depression after myocardial infarction

BACKGROUND

There is an increased incidence of major depressive disorder (MDD) in individuals after myocardial infarction (MI), but the pathophysiological processes mediating this association are unclear. Our previous study demonstrated an increase in pro-apoptotic pathways in the myocardium and hippocampus in MDD, which was reversed by venlafaxine. This study aimed to attempt to confirm the effects of apoptosis vulnerability markers on the myocardium in a model of depression after myocardial infarction.

METHODS

Rats were divided into four groups: sham (N = 8), depression (N = 8, chronic mild unpredictable stress and separation were used in the depression group), MI (N = 13) and post-MI depression (N = 7). The rats in all four groups underwent the same open field and sucrose preference behavioral tests. Evan Blue staining was used to determine the area at risk of myocardial infarction in the left ventricle, and 2,3,5-triphenyl tetrazolium chloride (1.5% TTC) dye was used to detect the size of the myocardial infarction. The expression of bax and bcl-2 protein in the myocardium was investigated by immunohistochemistry, and the mRNA expression of bax, bcl-2 and caspase-3 in the myocardium was investigated by real time RT-PCR. Apoptosis was estimated in the myocardium by measuring the Bax:Bcl-2 ratio.

RESULTS

In the depression and post-MI depression rats, there were significantly decreased movements and total sucrose consumption, modeling behavioral deficits and an anhedonic-like state. In terms of myocardial infarction size, no difference was seen between the MI and post-MI depression groups. There was an up-regulated Bax:Bcl-2 ratio in the depression, MI and post-MI depression groups. Furthermore, in the latter group, there was a greater up-regulated Bax:Bcl-2 ratio. However, caspase-3 did not differ among the four groups.

CONCLUSIONS

These results of this animal model suggest that active pro-apoptotic pathways may be involved in the nexus between myocardial infarction and depression. This mechanism may be germane to understanding this relationship in humans.

Attenuation of post-myocardial infarction depression in rats by n-3 fatty acids or probiotics starting after the onset of reperfusion. Br J Nutr. 2013;109:50-56. [PMID: 23068715 DOI: 10.1017/s0007114512003807]

Proinflammatory cytokines play a central role in depression-like behaviour and apoptosis in the limbic system after myocardial infarction (MI). A PUFA n-3 diet or the combination of Lactobacillus helveticus R0052 and Bifidobacterium longum R0175 probiotics, when given before the ischaemic period, reduce circulating proinflammatory cytokines as well as apoptosis in the limbic system. The present study was designed to determine if the same nutritional interventions maintain their beneficial effects when started after the onset of the reperfusion period and attenuate depression-like behaviour observed after MI. MI was induced by the occlusion of the left anterior descending coronary artery for 40 min in rats. After the onset of reperfusion, animals were fed with a high- or low-PUFA n-3 diet, combined or not with one billion live bacteria of L. helveticus and B. longum. At 3 d post-MI, caspase-3 enzymatic activities and terminal 2'-deoxyuridine, 5'-triphosphate (dUTP) nick-end labelling (TUNEL)-positive cells were decreased in the CA1, dentate gyrus (DG) and amygdala with the high-PUFA n-3 diet, as compared to the three other diets. Probiotics attenuated caspase-3 activity and TUNEL-positive cells in the DG and the medial amygdala. At 2 weeks post-MI, depression-like behaviour was observed in the low-PUFA n-3 diet without probiotics-group, and this behaviour was attenuated with the high-PUFA n-3 diet or/and probiotics. These results indicate that a high-PUFA n-3 diet or the administration of probiotics, starting after the onset of reperfusion, are beneficial to attenuate apoptosis in the limbic system and post-MI depression in the rat.

Icariin inhibits corticosterone-induced apoptosis in hypothalamic neurons via the PI3-K/Akt signaling pathway

Excessive corticosterone (CORT) is acknowledged to induce neuronal damage in a number of regions of the brain, particularly the hippocampus, the main area implicated in depression. However, little research has been conducted on alterations to hypothalamic neurons in depression and the cellular and molecular basis for these changes. In the present study, we aimed to determine whether CORT causes apoptosis in primary cultured hypothalamic neurons, and to investigate the protective effects of icariin, an active natural ingredient from the Chinese plant, Epimedium sagittatum Maxim. Our study demonstrates that exposure of hypothalamic neurons to CORT causes a significant loss in viability, a significant decrease in mitochondrial membrane potential, an increase in caspase-3 activity, an elevation in intracellular reactive oxygen species elevation and decreased superoxide dismutase activity. However, pretreatment of cells with icariin prior to CORT exposure was identified to noticeably suppress these CORT-induced events. Furthermore, icariin may prevent CORT-induced cell death via activation of the PI3-K/Akt pathway. In conclusion, icariin is able to prevent CORT-induced hypothalamic cell apoptosis via activation of the PI3-K/Akt pathway.

Combination of Lactobacillus helveticus R0052 and Bifidobacterium longum R0175 reduces post-myocardial infarction depression symptoms and restores intestinal permeability in a rat model

Myocardial infarction (MI) in rats is accompanied by apoptosis in the limbic system and a behavioural syndrome similar to models of depression. We have already shown that probiotics can reduce post-MI apoptosis and designed the present study to determine if probiotics can also prevent post-MI depressive behaviour. We also tested the hypothesis that probiotics achieve their central effects through changes in the intestinal barrier. MI was induced in anaesthetised rats via 40-min transient occlusion of the left anterior coronary artery. Sham rats underwent the same surgical procedure without actual coronary occlusion. For 7 d before MI and between the seventh post-MI day and euthanasia, half the MI and sham rats were given one billion live bacterial cells of Lactobacillus helveticus R0052 and Bifidobacterium longum R0175 per d dissolved in water, while the remaining animals received only the vehicle (maltodextrin). Depressive behaviour was evaluated 2 weeks post-MI in social interaction, forced swimming and passive avoidance step-down tests. Intestinal permeability was evaluated by oral administration with fluorescein isothiocyanate-dextran, 4 h before euthanasia. MI rats displayed less social interaction and impaired performance in the forced swimming and passive avoidance step-down tests compared to the sham controls (P < 0·05). Probiotics reversed the behavioural effects of MI (P < 0·05), but did not alter the behaviour of sham rats. Intestinal permeability was increased in MI rats and reversed by probiotics. In conclusion, L. helveticus R0052 and B. longum R0175 combination interferes with the development of post-MI depressive behaviour and restores intestinal barrier integrity in MI rats.

Effects of different dietary omega-6/3 polyunsaturated fatty acids ratios on infarct size and the limbic system after myocardial infarction

Changes in dietary omega-6/3 polyunsaturated fatty acids (PUFA) ratios affect anti- and proinflammatory equilibrium. As reperfused myocardial infarction (MI) is an inflammatory pathology that alters the cell integrity of the myocardium but also of other tissues, such as the hippocampus and amygdala, attenuation of the inflammation could be helpful in maintaining cell integrity after MI. Therefore, we hypothesized that a decrease in the dietary omega-6/3 PUFA ratio, without altering the diet content in total fat, proteins, or carbohydrates, will result in a reduction of infarct size and a diminution of postreperfusion apoptosis observed in the amygdala and hippocampus. Male Sprague–Dawley rats were fed 1 of 3 diets containing different omega-6/3 PUFA ratios for 2 weeks (5:1; 1:1; 1:5). Then, myocardial ischemia was induced by left anterior descending coronary artery occlusion for 40 min, followed by reperfusion. Cardioprotective mechanisms were studied in the myocardium at 15 min of reperfusion, along with myocardial infarct size after 24 h of reperfusion. Apoptosis was evaluated in the hippocampus and the amygdala. We found that infarct size was significantly reduced by 32% in groups 1:5 and 1:1 vs. group 5:1. Akt activity was higher in groups 1:5 and 1:1 compared with group 5:1. Caspase-3 enzymatic activity doubled in area CA1 and the dentate gyrus (DG) in group 5:1 compared with groups 1:1 and 1:5. In addition, caspase-8 enzymatic activity was increased in the DG at 24 h, and caspase-9 was enhanced in CA1 at 24 h in group 5:1 vs. groups 1:1 and 1:5. These results demonstrate that the increase in the dietary omega-3 PUFA, at the expense of omega-6 PUFA, reduces infarct size and helps to inhibit apoptosis in the limbic system after MI.

Inflammation and depression: why poststroke depression may be the norm and not the exception

Ischaemic stroke often precedes the appearance of clinical depression. Poststroke depression in turn influences the prognostic outcome. In the interest of advancing our understanding of the biological mechanisms underlying the development of poststroke depression, this systematic review explores the immunological processes driving the development of inflammation-related cell death in mood-related brain regions. Particular attention has been paid to cytokine-driven intrinsic apoptosis factors, including intracellular calcium, glutamate excitotoxicity and free radicals that appear in the brain following ischaemic damage and whose presence significantly increases the likelihood of clinically defined depression.

Paradoxical sleep insomnia and decreased cholinergic neurons after myocardial infarction in rats

STUDY OBJECTIVES

Acute myocardial infarction (MI) is followed, within a few hours, by neuronal loss in the central nervous system (CNS), including the limbic system, the hypothalamus, and the brainstem. Sleep before and after MI was investigated in the first experiment. In a parallel experiment, 2 weeks after MI, we quantified brainstem cholinergic neurons known to control paradoxical sleep (PS).

MEASUREMENTS AND RESULTS

Data were obtained from 28 adult male Sprague-Dawley rats weighing 350-375 g and maintained under a 12-12 light-dark cycle in 2 experiments on 16 and 12 rats, respectively. The 16 animals in the first experiment were implanted with chronic electroencephalographic (EEG) and electromyographic (EMG) electrodes. A week after surgery, these animals were habituated for 2 days to the recording equipment, and baseline sleep was charted for 24 h. The next morning, MI was induced in 8 rats by occluding the left anterior descending coronary artery for 40 min. The remaining 8 rats served as sham-operated controls. Sleep was recorded again 2 weeks after MI. The number of choline acetyltransferase (ChAT)-positive neurons was counted in the second, parallel experiment on 6 MI and 6 sham rats. Compared to the sham controls, MI rats displayed longer latency to sleep onset, shorter latency to paradoxical sleep (PS), and curtailed PS duration. The number of ChAT-positive neurons in the pedunculopontine tegmentum (PPT) area of MI rats was significantly decreased compared to the sham controls, while the number of laterodorsal tegmentum (LDT) cholinergic neurons was not different.

CONCLUSION

Acute MI is accompanied, within 2 weeks, by PS-specific insomnia that can be explained, at least partly, by a specific loss of cholinergic neurons in an area known to control PS.

Increased αB-crystallin in hypothalamic paraventricular nucleus of rats with myocardial infarction

The hypothalamus plays an important role in maintaining a homeostasis of the body against stress response. In particular, the paraventricular nucleus of the hypothalamus is a critical region for disorders related to the autonomic nervous system, such as congestive heart failure and hypertension. αB-crystallin is a family of heat shock proteins that are widely expressed in the brain, including in glial cells, astrocytes, oligodendrocytes, and neurons. Many studies have demonstrated that expression level of αB-crystallin is up-regulated and involved in protecting cells from pathological conditions. In the present study, we examined the expression and potential role of αB-crystallin in the paraventricular nucleus (PVN) regions of rats with myocardial infarction (MI). Our results demonstrate that mRNA encoding αB-crystallin and protein for both native and phosphorylate forms (Ser-59) of αB-crystallin was significantly increased in the PVN during MI.

13-Cis-retinoic acid decreases hypothalamic cell number in vitro

13-Cis-retinoic acid (13-cis-RA) causes depression-related behavior in mice. Hypothalamic dysregulation has been implicated in clinical depression. In fact, apoptosis of hypothalamic neurons may lead to depression after myocardial infarction. Our objective was to determine if 13-cis-RA affects cultured hypothalamic cell number. Treatment of GT1-7 hypothalamic cells with 10μM 13-cis-RA for 48h decreased cell growth to 45.6±13% of control. To determine if this decrease in cell number was due to 13-cis-RA acting as an oxidant, cells were treated with 13-cis-RA and ascorbic acid or butylated hydroxyanisole (BHA) for 24 or 48h. Neither antioxidant alleviated the inhibitory affects of 13-cis-RA. In addition, 13-cis-RA treatment did not increase superoxide anion production, indicating 13-cis-RA was not acting as an oxidant. To determine if 13-cis-RA was acting via retinoic acid receptors (RARs) to decrease cell number, GT1-7 cells were treated with 13-cis-RA and the RAR pan-antagonist, AGN 193109. Treatment with the RAR-antagonist blocked the ability of 13-cis-RA to decrease cell number, indicating this phenomenon was a RAR-independent mechanism. We hypothesize that the ability of 13-cis-RA to decrease hypothalamic cell number may contribute to the increased depression-related behaviors observed in mice.

Association of anhedonia with recurrent major adverse cardiac events and mortality 1 year after acute coronary syndrome

CONTEXT

Depression consistently predicts recurrent events and mortality in patients with acute coronary syndrome (ACS), but it has 2 core diagnostic criteria with distinct biological correlates-depressed mood and anhedonia (loss of pleasure or interest).

OBJECTIVE

To determine if depressed mood and/or anhedonia predict 1-year medical outcomes for patients with ACS.

DESIGN

Observational cohort study of post-ACS patients hospitalized between May 2003 and June 2005. Within 1 week of admission, patients underwent a structured psychiatric interview assessing clinically impairing depressed mood, anhedonia, and major depressive episode (MDE). Also assessed were the Global Registry of Acute Coronary Events risk score, Charlson comorbidity index, left ventricular ejection fraction, antidepressant use, and depressive symptom severity using the Beck Depression Inventory.

SETTING

Cardiac units of 3 university hospitals in New York and Connecticut.

PARTICIPANTS

Consecutive sample of 453 patients with ACS (age, 25-93 years; 42% women).

MAIN OUTCOMES MEASURES

All-cause mortality (ACM) and documented major adverse cardiac events (MACEs)-myocardial infarction, hospitalization for unstable angina, or urgent/emergency coronary revascularization)-actively surveyed for 1 year after admission.

RESULTS

There were 67 events (16 deaths and 51 MACEs; 14.8%): 108 (24%) and 77 (17%) patients had anhedonia and depressed mood, respectively. Controlling for sex, age, and medical covariates, anhedonia (adjusted hazard ratio, 1.58; 95% confidence interval, 1.16-2.14; P < .01) was a significant predictor of combined MACE and ACM, but depressed mood was not. Anhedonia continued to significantly predict outcomes (P < .05) when additionally controlling for MDE diagnosis or depressive symptom severity. Findings were confirmed using depressed mood and anhedonia subscores from the Beck Depression Inventory in place of clinician interview ratings.

CONCLUSIONS

Anhedonia identifies risk of MACE and ACM beyond that of established medical prognostic indicators, including MDE and depressive symptom severity. Correlates of anhedonia may add to the understanding of the link between depression and heart disease.

Simultaneous anhedonia and exaggerated locomotor activation in an animal model of depression

RATIONALE

Anhedonia, or hyposensitivity to normally pleasurable stimuli, is a cardinal symptom of depression. As such, reward circuitry may comprise a substrate with relevance to this symptom of depression.

OBJECTIVES

Our aim was to characterize in the rat changes in the rewarding properties of a pharmacological and a natural stimulus following olfactory bulbectomy (OBX), a pre-clinical animal model of depression.

METHODS

We measured amphetamine enhancement of brain stimulation reward, changes in sucrose intake, as well as striatal cAMP response element binding protein (CREB) activity, a molecular index previously associated with depressant-like behavior. Moreover, since alteration of psychomotor activity is also a common symptom of depression, and psychostimulant reward and locomotion are thought to share common neurobiology, we used the same treatment schedule of amphetamine to probe for changes in locomotion.

RESULTS

Our findings show that OBX produces a behavioral phenotype characterized by both anhedonia and exaggerated locomotor activation. Thus, we observed a blunted response to the rewarding properties of amphetamine (1 mg/kg, 21 days post-lesion), a long-lasting reduction in sucrose intake and increased striatal CREB activity. In addition, the same dose of amphetamine, at a coincident time post-lesion, triggered an exaggerated response to its locomotor-stimulant actions.

CONCLUSIONS

These paradoxical findings are not consistent with the notion that reward and locomotion are mediated by a common substrate; this dissociation may be useful in modeling psychiatric disorders such as mixed depressive states. In addition, our findings suggest that central reward circuitry may constitute a possible target for rationally designed therapeutics for depression.

Lactobacillus helveticus and Bifidobacterium longum taken in combination reduce the apoptosis propensity in the limbic system after myocardial infarction in a rat model

Myocardial infarction (MI) stimulates the release of pro-inflammatory substances that induce apoptosis in the limbic system. Pro-inflammatory cytokines are considered as the root cause of apoptosis, although the mechanism is not fully explained and/or understood at this time. In addition, depression may induce gastrointestinal perturbations that maintain the elevated levels of pro-inflammatory cytokines. It has been shown that some specific probiotic formulations may reduce gastrointestinal problems induced by stress and the pro/anti-inflammatory cytokine ratio. Therefore, we hypothesised that probiotics, when given prophylactically, may diminish the apoptosis propensity in the limbic system following a MI. Male adult Sprague–Dawley rats were given probiotics (Lactobacillus helveticus and Bifidobacterium longum in combination) or placebo in their drinking-water for four consecutive weeks. A MI was then induced in the rats by occluding the left anterior coronary artery for 40 min. Rats were killed following a 72 h reperfusion period. Infarct size was not different in the two groups. Bax/Bcl-2 (pro-apoptotic/anti-apoptotic) ratio and caspase-3 (pro-apoptotic) activity were reduced in the amygdala (lateral and medial), as well as in the dentate gyrus in the probiotics group when compared with the placebo. Akt activity (anti-apoptotic) was increased in these same three regions. No significant difference was observed in Ca1 and Ca3 for the different markers measured. In conclusion, the probiotics L. helveticus and B. longum, given in combination as preventive therapy, reduced the predisposition of apoptosis found in different cerebral regions following a MI.