Targeting the renin angiotensin system for the treatment of anxiety and depression

Evaluation of Anxiolytic Activity of Angiotensin Receptor Blockers Using Actophotometer Test in Wistar Rats

Introduction Anxiety disorders are common mental illnesses impacting quality of life, with current treatments like benzodiazepines and selective serotonin reuptake inhibitors (SSRIs) facing limitations due to side effects. Angiotensin receptor blockers (ARBs), used primarily for hypertension, have shown potential neuropsychiatric benefits, including anxiolytic effects. This study explores the anxiolytic effects of two ARBs, telmisartan and losartan, by evaluating locomotor activity in Wistar rats, aiming to identify new treatment options for anxiety through modulation of the renin-angiotensin system. Aim To evaluate the anxiolytic activity of telmisartan and losartan in experimental Wistar rats. Materials and methods The study was carried out after consent was obtained from the Institutional Animal Ethics Committee (IAEC). The rats were divided into four groups: group 1 (control group) received distilled water (2 ml/kg), group 2 (diazepam 2 mg/kg group) received diazepam (2 mg/kg), group 3 (telmisartan 5 mg/kg group) received telmisartan (5 mg/kg), and group 4 (losartan 5 mg/kg group) received losartan (5 mg/kg). The actophotometer test, which measures the locomotor activity levels of rats, was utilized to evaluate their anxiolytic activity. The percent decrease in locomotor activity was calculated for statistical evaluation. Results Our investigation found that the telmisartan 5 mg/kg and losartan 5 mg/kg groups had considerable anxiolytic activity (p<0.05) compared to the control group, and it was comparable to the diazepam 2 mg/kg (p>0.05) group. Conclusion The findings of our study indicate that ARBs, specifically telmisartan 5 mg/kg and losartan 5 mg/kg, exhibit potential anxiolytic effects, evidenced by a significant reduction in locomotor activity in the actophotometer test. These results imply that ARBs could be considered as possible therapeutic agents for anxiety, providing a new perspective on their use beyond traditional cardiovascular applications.

Anxiolytic effect of alamandine in male transgenic rats with low brain angiotensinogen is dependent on activation of MrgD receptors

Alamandine is a peptide hormone belonging to the renin-angiotensin system (RAS). It acts through the Mas-related G-protein coupled receptor type D, MrgD, which is expressed in different tissues, including the brain. In the present study, we hypothesize that a lack of alamandine, through MrgD, could cause the anxiety-like behavior in transgenic rats with low brain angiotensinogen [TGR(ASrAOGEN)680]. Adult male transgenic rats exhibited a significant increase in the latency to feeding time in the novelty suppressed feeding test and a decrease in the percentage of time and entries in the open arms in the elevated plus maze. These effects were reversed by intracerebroventricular infusion of alamandine. Pretreatment with D-Pro7-Ang-(1-7), a Mas and MrgD receptor antagonist, prevented the anxiolytic effects induced by this peptide. However, its effects were not altered by the selective Mas receptor antagonist, A779. In conclusion, our data indicates that alamandine, through MrgD, attenuates anxiety-like behavior in male TGR(ASrAOGEN)680, which reinforces the importance of the counter-regulatory RAS axis as promising target for the treatment of neuropsychiatric disorders.

Association between white matter hyperintensity and anxiety/depression

Although previous studies have explored the associations of white matter hyperintensity with psychiatric disorders, the sample size is small and the conclusions are inconsistent. The present study aimed to further systematically explore the association in a larger sample. All data were extracted from the UK Biobank. First, general linear regression models and logistic regression models were used to assess the association between white matter hyperintensity volume and anxiety/depression. White matter hyperintensity has been classified into periventricular white matter hyperintensity and deep white matter hyperintensity. Anxiety was determined by General Anxiety Disorder-7 score (n = 17,221) and self-reported anxiety (n = 15,333), depression was determined by Patient Health Questionnaire-9 score (n = 17,175), and self-reported depression (n = 14,519). Moreover, we employed Cox proportional hazard models to explore the association between white matter hyperintensity volume and anxiety/depression. The covariates included in fully adjusted model are age, gender, body mass index, Townsend deprivation index, healthy physical activity, cigarette consumption, alcohol consumption, educational attainment, diabetes, hypertension, and coronary heart disease. The results of the fully adjusted model showed that white matter hyperintensity volume was significantly associated with General Anxiety Disorder-7 score (periventricular white matter hyperintensity: β = 0.152, deep white matter hyperintensity: β = 0.094) and Patient Health Questionnaire-9 score (periventricular white matter hyperintensity: β = 0.168). Logistic regression analysis results indicated that periventricular white matter hyperintensity volume (odds ratio = 1.153) was significantly associated with self-reported anxiety. After applying the Cox proportional hazard models, we found that larger white matter hyperintensity volume was associated with increased risk of depression (periventricular white matter hyperintensity: hazard ratio = 1.589, deep white matter hyperintensity: hazard ratio = 1.200), but not anxiety. In summary, our findings support a positive association between white matter hyperintensity volume and depression.

Global epidemiology of mental disorder in atrial fibrillation between 1998-2021: A systematic review and meta-analysis

BACKGROUND

As the burden of mental disorders among patients with atrial fibrillation (AF) increases, researchers are beginning to pay close attention to the risk and prevalence of these comorbidities. Although studies have independently analyzed the risk of comorbidity with depression and anxiety in patients with AF, no study has systematically focused on the global epidemiology of these two mental disorders.

AIM

To explore the prevalence of depression and anxiety in patients with AF.

METHODS

Five databases were searched from their date of establishment until January 2023. Observational studies reporting the comorbidity of AF with depression and anxiety, were included in this study. Basic information, such as the first author/ publication year, study year, study type, and prevalence of depression and anxiety, were extracted. STATA SE 15.1 was used to analyze the data. Subgroup, meta-regression, and sensitivity analyses were performed to estimate study heterogeneity.

RESULTS

After a thorough search, 26 studies were identified and included in this meta-analysis. The prevalence rates of depression and anxiety in adults with AF were 24.3% and 14.5%, respectively. Among adult males with AF, the prevalence was 11.7% and 8.7%, respectively, whereas in females it was 19.8% and 10.1%, respectively. In older adults with AF, the prevalence rates of depression and anxiety were 40.3% and 33.6%, respectively. The highest regional prevalence of depression and anxiety was observed in European (30.2%) and North American (19.8%) patients with AF.

CONCLUSION

In this study, we found that the prevalence of depression and anxiety among patients with AF varies with sex, region, and evaluation scales, suggesting the need for psychological interventions for patients with AF in clinical practice.

Neuroproteomics: Unveiling the Molecular Insights of Psychiatric Disorders with a Focus on Anxiety Disorder and Depression

Anxiety and depression are two of the most common mental disorders worldwide, with a lifetime prevalence of up to 30%. These disorders are complex and have a variety of overlapping factors, including genetic, environmental, and behavioral factors. Current pharmacological treatments for anxiety and depression are not perfect. Many patients do not respond to treatment, and those who do often experience side effects. Animal models are crucial for understanding the complex pathophysiology of both disorders. These models have been used to identify potential targets for new treatments, and they have also been used to study the effects of environmental factors on these disorders. Recent proteomic methods and technologies are providing new insights into the molecular mechanisms of anxiety disorder and depression. These methods have been used to identify proteins that are altered in these disorders, and they have also been used to study the effects of pharmacological treatments on protein expression. Together, behavioral and proteomic research will help elucidate the factors involved in anxiety disorder and depression. This knowledge will improve preventive strategies and lead to the development of novel treatments.

Global Prevalence of Anxiety in Adult Cardiology Outpatients: A Systematic Review and Meta-analysis

Anxiety and anxiety disorders are associated with adverse cardiovascular outcomes, and reduced quality of life. Despite this, no comprehensive study on the global prevalence of anxiety symptoms and disorders among adult cardiology outpatients exists. This systematic review and meta-analysis aims to provide cardiologists with a precise estimate of the prevalence of anxiety in their outpatient clinics. PubMed, Embase, Cochrane and PsycINFO databases and Google Scholar were searched from database inception to January 23, 2023. Data characteristics were extracted independently by 2 investigators. Ninety-three studies, n = 36,687 participants across 31 countries, were included. Global prevalence of anxiety symptoms/disorders was 28.9% (95%CI 25.7-32.4; 8927/36, 687; I2 = 97.33; n = 93). The highest rates were found in patients presenting with hypertension, 43.6%. Subgroup analyses revealed higher prevalence estimates when using self-report screening compared to gold-standard diagnostic interview. When using diagnostic interview, the highest rates were reported in outpatients with undifferentiated chest pain/palpitations, 19·0%. Panic disorder was the most frequent diagnosis 15.3%, and rates were significantly higher in patients with undifferentiated chest pain/palpitations compared to ischemic heart disease. Higher rates of anxiety were found in studies of outpatients from developing countries, and female outpatients tended to have higher rates compared to males. Anxiety occurred frequently among cardiology outpatients and at a higher rate than estimated in the general population. Given the impact anxiety has on patient outcomes, it is important that effective identification and management strategies be developed to support cardiologists in identifying and treating these conditions in their clinics.

Depression and atrial fibrillation in a reciprocal liaison: a neuro-cardiac link

OBJECTIVE

To explore the reciprocal relationship of depression and atrial fibrillation (AF).

METHODS

A literature search was conducted in Pub Med, Scopus, and Google Scholar using relevant terms for depression and AF and respective therapies.

RESULTS

There is evidence that depression is involved in the aetiology and prognosis of AF. AF, independently of its type, incurs a risk of depression in 20-40% of patients. Also, depression significantly increases cumulative incidence of AF (from 1.92% to 4.44% at 10 years); 25% increased risk of new-onset AF is reported in patients with depression, reaching 32% in recurrent depression. Hence, emphasis is put on the importance of assessing depression in the evaluation of AF and vice versa. Persistent vs paroxysmal AF patients may suffer from more severe depression. Furthermore, depression can impact the effectiveness of AF treatments, including pharmacotherapy, anticoagulation, cardioversion and catheter ablation.

CONCLUSIONS

A reciprocal association of depression and AF, a neurocardiac link, has been suggested. Thus, strategies which can reduce depression may improve AF patients' course and treatment outcomes. Also, AF has a significant impact on risk of depression and quality of life. Hence, effective antiarrhythmic therapies may alleviate patients' depressive symptoms. KEY POINTSAF, independently of its type of paroxysmal, permanent or chronic, appears to have mental besides physical consequences, including depression and anxietyA reciprocal influence or bidirectional association of depression and AF, a neurocardiac link, has been suggestedAF has considerable impact on the risk of depression occurrence with 20-40% of patients with AF found to have high levels of depressionAlso, depression significantly increases 10-year cumulative incidence and risk of AF from 1.92% to 4.44% in people without depression, and the risk of new-onset AF by 25-32%Emphasis should be placed on the importance of assessing depression in the evaluation of AF and vice versaPersistent/chronic AF patients may suffer from more severe depressed mood than paroxysmal AF patients with similar symptom burdenDepression and anxiety can impact the effectiveness of certain AF treatments, including pharmacotherapy, anticoagulation treatment, cardioversion and catheter ablationThus, strategies which can reduce anxiety and depression may improve AF patients' course and treatment outcomesAlso, effective antiarrhythmic therapies to control AF may alleviate patients' depressive mood.

The Renin Angiotensin System as a Therapeutic Target in Traumatic Brain Injury

Traumatic brain injury (TBI) is a major public health problem, with limited pharmacological options available beyond symptomatic relief. The renin angiotensin system (RAS) is primarily known as a systemic endocrine regulatory system, with major roles controlling blood pressure and fluid homeostasis. Drugs that target the RAS are used to treat hypertension, heart failure and kidney disorders. They have now been used chronically by millions of people and have a favorable safety profile. In addition to the systemic RAS, it is now appreciated that many different organ systems, including the brain, have their own local RAS. The major ligand of the classic RAS, Angiotensin II (Ang II) acts predominantly through the Ang II Type 1 receptor (AT1R), leading to vasoconstriction, inflammation, and heightened oxidative stress. These processes can exacerbate brain injuries. Ang II receptor blockers (ARBs) are AT1R antagonists. They have been shown in several preclinical studies to enhance recovery from TBI in rodents through improvements in molecular, cellular and behavioral correlates of injury. ARBs are now under consideration for clinical trials in TBI. Several different RAS peptides that signal through receptors distinct from the AT1R, are also potential therapeutic targets for TBI. The counter regulatory RAS pathway has actions that oppose those stimulated by AT1R signaling. This alternative pathway has many beneficial effects on cells in the central nervous system, bringing about vasodilation, and having anti-inflammatory and anti-oxidative stress actions. Stimulation of this pathway also has potential therapeutic value for the treatment of TBI. This comprehensive review will provide an overview of the various components of the RAS, with a focus on their direct relevance to TBI pathology. It will explore different therapeutic agents that modulate this system and assess their potential efficacy in treating TBI patients.

Integrated bioinformatics and statistical approach to identify the common molecular mechanisms of obesity that are linked to the development of two psychiatric disorders: Schizophrenia and major depressive disorder

Obesity is a chronic multifactorial disease characterized by the accumulation of body fat and serves as a gateway to a number of metabolic-related diseases. Epidemiologic data indicate that Obesity is acting as a risk factor for neuro-psychiatric disorders such as schizophrenia, major depression disorder and vice versa. However, how obesity may biologically interact with neurodevelopmental or neurological psychiatric conditions influenced by hereditary, environmental, and other factors is entirely unknown. To address this issue, we have developed a pipeline that integrates bioinformatics and statistical approaches such as transcriptomic analysis to identify differentially expressed genes (DEGs) and molecular mechanisms in patients with psychiatric disorders that are also common in obese patients. Biomarker genes expressed in schizophrenia, major depression, and obesity have been used to demonstrate such relationships depending on the previous research studies. The highly expressed genes identify commonly altered signalling pathways, gene ontology pathways, and gene-disease associations across disorders. The proposed method identified 163 significant genes and 134 significant pathways shared between obesity and schizophrenia. Similarly, there are 247 significant genes and 65 significant pathways that are shared by obesity and major depressive disorder. These genes and pathways increase the likelihood that psychiatric disorders and obesity are pathogenic. Thus, this study may help in the development of a restorative approach that will ameliorate the bidirectional relation between obesity and psychiatric disorder. Finally, we also validated our findings using genome-wide association study (GWAS) and whole-genome sequence (WGS) data from SCZ, MDD, and OBE. We confirmed the likely involvement of four significant genes both in transcriptomic and GWAS/WGS data. Moreover, we have performed co-expression cluster analysis of the transcriptomic data and compared it with the results of transcriptomic differential expression analysis and GWAS/WGS.

Angiotensinergic neurotransmission in the bed nucleus of the stria terminalis is involved in cardiovascular responses to acute restraint stress in rats

The brain angiotensin II acting via AT₁ receptors is a prominent mechanism involved in physiological and behavioral responses during aversive situations. The AT₂ receptor has also been implicated in stress responses, but its role was less explored. Despite these pieces of evidence, the brain sites related to control of the changes during aversive threats by the brain renin-angiotensin system (RAS) are poorly understood. The bed nucleus of the stria terminalis (BNST) is a limbic structure related to the cardiovascular responses by stress, and components of the RAS system were identified in this forebrain region. Therefore, we investigated the role of angiotensinergic neurotransmission present within the BNST acting via local AT₁ and AT₂ receptors in cardiovascular responses evoked by an acute session of restraint stress in rats. For this, rats were subjected to bilateral microinjection of either the angiotensin-converting enzyme inhibitor captopril, the selective AT₁ receptor antagonist losartan, or the selective AT₂ receptor antagonist PD123319 before they underwent the restraint stress session. We observed that BNST treatment with captopril reduced the decrease in tail skin temperature evoked by restraint stress, without affecting the pressor and tachycardic responses. Local AT₂ receptor antagonism within the BNST reduced both the tachycardia and the drop in tail skin temperature during restraint. Bilateral microinjection of losartan into the BNST did not affect the restraint-evoked cardiovascular changes. Taken together, these data indicate an involvement of BNST angiotensinergic neurotransmission acting via local AT₂ receptors in cardiovascular responses during stressful situations.

Angiotensin II Regulates the Neural Expression of Subjective Fear in Humans: A Precision Pharmaco-Neuroimaging Approach

BACKGROUND

Rodent models and pharmacological neuroimaging studies in humans have been used to test novel pharmacological agents to reduce fear. However, these strategies are limited with respect to determining process-specific effects on the actual subjective experience of fear, which represents the key symptom that motivates patients to seek treatment. In this study, we used a novel precision pharmacological functional magnetic resonance imaging approach based on process-specific neuroaffective signatures to determine effects of the selective angiotensin II type 1 receptor (AT1R) antagonist losartan on the subjective experience of fear.

METHODS

In a double-blind, placebo-controlled, randomized pharmacological functional magnetic resonance imaging design, healthy participants (N = 87) were administered 50 mg losartan or placebo before they underwent an oddball paradigm that included neutral, novel, and fear oddballs. Effects of losartan on brain activity and connectivity as well as on process-specific multivariate neural signatures were examined.

RESULTS

AT1R blockade selectively reduced neurofunctional reactivity to fear-inducing visual oddballs in terms of attenuating dorsolateral prefrontal activity and amygdala-ventral anterior cingulate communication. Neurofunctional decoding further demonstrated fear-specific effects in that AT1R blockade reduced the neural expression of subjective fear but not of threat or nonspecific negative affect and did not influence reactivity to novel oddballs.

CONCLUSIONS

These results show a specific role of the AT1R in regulating the subjective fear experience and demonstrate the feasibility of a precision pharmacological functional magnetic resonance imaging approach to the affective characterization of novel receptor targets for fear in humans.

Impact of genetic deletion of MrgD or Mas receptors in depressive-like behaviour in mice

OBJECTIVES

To evaluate the impact of genetic deletion of receptors of the counterregulatory arms of the renin-angiotensin system in depressive-like behaviours.

METHODS

8-12 weeks-old male mice wild type (WT, C57BL/6J) and mice with genetic deletion of MrgD (MrgD KO) or Mas receptors (Mas KO) were subjected to the Forced Swim Test (FST) and the Tail Suspension Test (TST). Brain-derived neurotrophic factor (BDNF) levels were measured by enzyme-linked immunosorbent assay (ELISA). Blockade of Mas was performed by acute intracerebroventricular (icv) injection of its selective antagonist, A779.

RESULTS

No statistical difference in immobility time was observed between MrgD KO and WT male animals subjected to FST and TST. However, acute icv injection of A779 significantly increased the immobility time of MrgD KO male mice subjected to FST and TST, suggesting the involvement of Mas in preventing depressive-like behaviour. Indeed, Mas KO male animals showed increased immobility time in FST and TST, evidencing a depressive-like behaviour in these animals, in addition to a reduction in BDNF levels in the prefrontal cortex and hippocampus. No changes in BDNF levels were observed in MrgD KO male animals.

CONCLUSION

Our data showed that Mas plays an important role in the neurobiology of depression probably by modulating BDNF expression. On the contrary, lack of MrgD did not alter depressive-like behaviour, which was supported by the lack of alterations in BDNF levels.

Melatonin as a Potential Approach to Anxiety Treatment

Anxiety disorders are the most common mental diseases. Anxiety and the associated physical symptoms may disturb social and occupational life and increase the risk of somatic diseases. The pathophysiology of anxiety development is complex and involves alterations in stress hormone production, neurosignaling pathways or free radical production. The various manifestations of anxiety, its complex pathophysiological background and the side effects of available treatments underlie the quest for constantly seeking therapies for these conditions. Melatonin, an indolamine produced in the pineal gland and released into the blood on a nightly basis, has been demonstrated to exert anxiolytic action in animal experiments and different clinical conditions. This hormone influences a number of physiological actions either via specific melatonin receptors or by receptor-independent pleiotropic effects. The underlying pathomechanism of melatonin's benefit in anxiety may reside in its sympatholytic action, interaction with the renin-angiotensin and glucocorticoid systems, modulation of interneuronal signaling and its extraordinary antioxidant and radical scavenging nature. Of importance, the concentration of this indolamine is significantly higher in cerebrospinal fluid than in the blood. Thus, ensuring sufficient melatonin production by reducing light pollution, which suppresses melatonin levels, may represent an endogenous neuroprotective and anxiolytic treatment. Since melatonin is freely available, economically undemanding and has limited side effects, it may be considered an additional or alternative treatment for various conditions associated with anxiety.

Brain-heart communication in health and diseases

Tight connections between the brain and heart have attracted a considerable amount of attention. This review focuses on the anatomical (extrinsic cardiac autonomic nervous system and intrinsic cardiac autonomic nervous system) and functional (neuroendocrine-heart axis and neuroimmune-heart axis) connections between the brain and heart, the linkage between central nervous system diseases and cardiovascular diseases, the harm of sympathetic hyperactivity to the heart, and current neuromodulation therapies. Depression is a comorbidity of cardiovascular diseases, and the two are causally related. This review summarizes the mechanisms and treatment of depression and cardiovascular diseases, providing theoretical evidence for basic research and clinical studies to improve treatment options.

Impact of ACE2 genetic variant on antidepressant efficacy of SSRIs

Identification of a new axis of angiotensin-converting enzyme 2 (ACE2)/angiotensin (1-7)/Mas receptor, in the renin-angiotensin system (RAS), has opened a new insight regarding the role of RAS and angiotensin in higher brain functions. ACE2 catabolizes angiotensin II and produces angiotensin (1-7), an agonist of Mas receptor. Mice lacking the Mas receptor (angiotensin 1-7 receptor) exhibit anxiety-like behaviours. The present study was conducted to test the hypothesis of the involvement of ACE2 genetic variant (G8790A) on response to selective serotonin reuptake inhibitors (SSRIs). In a randomised control trial, 200 newly diagnosed Iranian patients with major depressive disorder completed 6 weeks of fluoxetine or sertraline treatment. Patients with a reduction of 50% or more in the Hamilton Rating Scale for Depression score were considered responsive to treatment. G8790A polymorphism was determined in extracted DNAs using restriction fragment length polymerase chain reaction method. Our results show that the A allele and AA and GA genotypes were significantly associated with better response to SSRIs (p = 0.008; OR = 3.4; 95% CI = 1.4-8.5 and p = 0.027; OR = 3.3, 95% CI = 1.2-9.2, respectively). Moreover, patients with GA and AA genotypes responded significantly better to sertraline (p = 0.0002; OR = 9.1; 95% CI = 2.4-33.7). The A allele was significantly associated with better response to sertraline (p = 0.0001; OR = 7.6; 95% CI = 2.5-23.3). In conclusion, our results confirm the role of G8790A in response to some SSRIs.

Anxiety is associated with higher recurrence of atrial fibrillation after catheter ablation: A meta‐analysis

Previous studies that evaluated the influence of anxiety on recurrence of atrial fibrillation (AF) after catheter ablation showed inconsistent results. We performed a meta‐analysis of cohort study to systematically evaluate the association between anxiety and AF recurrence after catheter ablation. Electronic databases of PubMed, Embase, and Web of Science were searched for relevant cohort studies from inception to January 20, 2021. We applied the random‐effect model to combine the results to incorporate the potential influence of heterogeneity among studies. Five cohort studies were eligible for the meta‐analysis, which included 549 patients with AF that received catheter ablation. No significant heterogeneity was observed among the included studies (I² = 7%, P for Cochrane's Q test = 0.37). During a mean follow‐up of 9.7 months, 216 (39.3%) cases of recurrent AF occurred. Results of the meta‐analysis showed that anxiety was independently associated with an increased risk of AF recurrence after catheter ablation (adjusted relative risk: 2.36, 95% confidence interval: 1.71–3.26; p < .001). Subgroup analyses did not show that differences in study characteristics including study design, ethnicity of the patients, sample size, AF type, anxiety evaluation method, follow‐up duration, or adjustment of LAD may significantly affect the association between anxiety and AF recurrence (p for subgroup difference all > .10). Anxiety may be an independent risk factor for AF recurrence after catheter ablation. Whether alleviating anxiety mood could reduce the risk of AF recurrence after catheter ablation should also be investigated.