Towards a personalized treatment in depression: endocannabinoids, inflammation and stress response

Does extreme psychological burden (Hamas terrorist attack on October 7th, 2023) affect in vitro fertilization outcome?

OBJECTIVE

We aim to investigate the effect of extreme emotional and psychological trauma following Hamas terrorist attack on October 7th, 2023, on IVF cycle outcome.

PATIENTS AND METHODS

The study population consisted of all couples undergoing 2 consecutive IVF attempts with ovum pick-up in our institute, before and during the week of October 8th to 12th, 2023. Embryological/ laboratory variables of the IVF cycles were assessed and compared between the patients' IVF cycle before and those that underwent OPU during the spoken week.

RESULTS

Twenty-three couples were eligible for analysis. There were no differences between the cycles in the length of ovarian stimulation, total dose of gonadotropin used, and the peak estradiol and progesterone levels. Furthermore, while no differences were observed in the number of oocytes and mature oocytes retrieved or fertilization rate, the mean number of top-quality embryos per OPU (1.1 ± 1.7 vs. 2.2 ± 2.9; p < 0.02) and ratio of top-quality embryos per number of fertilized oocytes (0.5 ± 0.3 vs. 0.7 ± 0.2; p < 0.01) were significantly lower during the spoken week. Semen total motile count was significantly reduced during the spoken week.

CONCLUSIONS

In the present study, we are witness to the effect of acute emotional and psychological trauma on IVF outcome, as reflected by its detrimental effect on sperm and embryo quality.

Effects of physical activity in child and adolescent depression and anxiety: role of inflammatory cytokines and stress-related peptide hormones

Depression and anxiety are the most common mental illnesses affecting children and adolescents, significantly harming their well-being. Research has shown that regular physical activity can promote cognitive, emotional, fundamental movement skills, and motor coordination, as a preventative measure for depression while reducing the suicide rate. However, little is known about the potential role of physical activity in adolescent depression and anxiety. The studies reviewed in this paper suggest that exercise can be an effective adjunctive treatment to improve depressive and anxiety symptoms in adolescents, although research on its neurobiological effects remains limited.

Is depression in patients with temporal lobe epilepsy related to hippocampal sclerosis? A meta-analysis

OBJECTIVE

To systematically evaluate the association between hippocampal sclerosis (HS) and depression in patients with temporal lobe epilepsy (TLE) through a meta-analysis.

METHODS

Chinese and English databases, such as the China National Knowledge Infrastructure (CNKI), Chinese Scientific Journals (VIP), WanFang, the Chinese Biomedical Literature Service System (SinoMed), PubMed and the Web of Science, were searched.

RESULTS

Two evaluators independently screened the literature, extracted data and evaluated the risk of bias in the included studies in accordance with the inclusion and exclusion criteria. RevMan 5.1 was used to analyze the data. A total of 786 patients with epilepsy were included in the study, including 82 depressive patients with HS and 64 depressive patients without HS. The results showed that the TLE patients with HS were more likely to develop depression than those without HS (odds ratio (OR)= 2.14, 95% confidence interval (CI) [1.45, 3.16], Z = 3.85, p = 0.0001).

CONCLUSION

HS can be considered a high-risk factor for depression in patients with TLE, and the correlation is significant. However, the sample size included in the study was small; additional high-quality studies are needed in the future.

Current Perspectives on Pharmacological and Non-Pharmacological Interventions for the Inflammatory Mechanism of Unipolar Depression

Since depression remains a major public health issue there is a constant need for new and more efficient therapeutic strategies based on the mechanisms involved in the aetiology of depression. Thus, the pathogenic link between depression and inflammation is considered to play a potential key role in the development of such therapies. This review summarizes the results of various pharmacological (non-steroidal anti-inflammatory drugs, aspirin, cyclooxygenase inhibitors, cytokine inhibitors, corticosteroids, statins, minocycline, N-acetyl cysteine, omega-3 fatty acids and probiotics) and non-pharmacological interventions (electroconvulsive therapy, physical exercise and psychological therapy) and outlines their efficacy and discusses potential challenges. Both conventional and non-conventional anti-inflammatory drugs showed promising results according to the specific group of patients. The pre-existing pro-inflammatory status was, in most cases, a predictor for clinical efficacy and, in some cases, a correlation between clinical improvement and changes in various biomarkers was found. Some of the non-pharmacological interventions (physical exercise and electroconvulsive therapy) have also showed beneficial effects for depressive patients with elevated inflammatory markers. Treatments with anti-inflammatory action may improve clinical outcomes in depression, at least for some categories of patients, thus opening the way for a future personalised approach to patients with unipolar depression regarding the inflammation-related mechanism.

A systematic review of the association between biological markers and environmental stress risk factors for adolescent depression

INTRODUCTION

Although the aetiology and pathophysiology of depression are multifactorial, to date most studies have examined either biological or environmental mechanisms without looking at the integration of both; with most studies conducted in high-income countries (HICs). Therefore, we conducted a systematic review of worldwide studies investigating the relationship between biological and environmental stress risk factors for major depressive disorder (MDD) in adolescence.

METHODS

We searched MEDLINE (via Ovid), PsycINFO, Cochrane Database of Systematic Reviews, Web of Science (Core Collection), Lilacs, African Journals Online and Global Health for prospective and cross-sectional studies that examined the association between biological markers and environmental stress risk factors in MDD during adolescence.

FINDINGS

Of 11,089 articles identified, 21 were included, with only two from middle-income countries. Increased inflammation, telomere length and brain abnormalities, including blunted reward-related activity, white matter disruptions, and altered volume of limbic brain regions, were associated with increased risk for MDD mainly in the context of early life adversity. There is little evidence suggesting that the neurobiological changes investigated were associated with MDD in the context of recent life stress.

INTERPRETATION

The developmental trajectory of depression appears to start with early life adversities and occurs in the context of immune and brain abnormalities. Understanding these biopsychosocial processes will help to improve our ability to detect individuals at risk of developing depression in adolescence. However, generalizability is limited by few studies examining both biological and environmental stress risk factors and a lack of studies on adolescents and young adults in low-and-middle-income countries (LMICs).

Detection of copy number variants in African goats using whole genome sequence data

Background

Copy number variations (CNV) are a significant source of variation in the genome and are therefore essential to the understanding of genetic characterization. The aim of this study was to develop a fine-scaled copy number variation map for African goats. We used sequence data from multiple breeds and from multiple African countries.

Results

A total of 253,553 CNV (244,876 deletions and 8677 duplications) were identified, corresponding to an overall average of 1393 CNV per animal. The mean CNV length was 3.3 kb, with a median of 1.3 kb. There was substantial differentiation between the populations for some CNV, suggestive of the effect of population-specific selective pressures. A total of 6231 global CNV regions (CNVR) were found across all animals, representing 59.2 Mb (2.4%) of the goat genome. About 1.6% of the CNVR were present in all 34 breeds and 28.7% were present in all 5 geographical areas across Africa, where animals had been sampled. The CNVR had genes that were highly enriched in important biological functions, molecular functions, and cellular components including retrograde endocannabinoid signaling, glutamatergic synapse and circadian entrainment.

Conclusions

This study presents the first fine CNV map of African goat based on WGS data and adds to the growing body of knowledge on the genetic characterization of goats.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12864-021-07703-1.

A systematic, integrative review of the effects of the endocannabinoid system on inflammation and neurogenesis in animal models of affective disorders

The endocannabinoid (eCB) system is considered relevant in the pathophysiology of affective disorders, and a potential therapeutic target, as its hypoactivity is considered an important risk factor of depression. However, the biological mechanisms whereby the eCB system affects mood remain elusive. Through a systematic review, thirty-seven articles were obtained from the PubMed/Medline, Web of Science, Embase, PsychInfo, and CINAHL databases, investigating the role of the eCB system on the immune system and neurogenesis, as well as resulting behavioural effects in rodent models of affective disorders. Overall, activation of the eCB system appears to decrease depressive-like behaviour and to be anti-inflammatory, while promoting neuro- and synaptogenesis in various models. Activation of cannabinoid receptors (CBRs) is shown to be crucial in improving depressive-like and anxiety-like behaviour, although cannabidiol administration suggests a role of additional mechanisms. CB₁R signalling, as well as fatty acid amide hydrolase (FAAH) inhibition, are associated with decreased pro-inflammatory cytokines. Moreover, activation of CBRs is required for neurogenesis, which is also upregulated by FAAH inhibitors. This review is the first to assess the association between the eCB system, immune system and neurogenesis, alongside behavioural outcomes, across rodent models of affective disorders. We confirm the therapeutic potential of eCB system activation in depression and anxiety, highlighting immunoregulation as an important mechanism whereby dysfunctional behaviour and neurogenesis can be improved.

Cannabinoids as therapeutics for PTSD

Post-traumatic stress disorder (PTSD) is a complex disorder that involves dysregulation of multiple neurobiological systems. The traumatic stressor plays a causal role in producing psychological dysfunction and the pattern of findings suggests that the hypothalamic-pituitary-adrenal (HPA) axis, which is instrumental for stress adaptation, is critically dysfunctional in PTSD. Given the lack of understanding of the basic mechanisms and underlying pathways that cause the disorder and its heterogeneity, PTSD poses challenges for treatment. Targeting the endocannabinoid (ECB) system to treat mental disorders, and PTSD in particular, has been the focus of research and interest in recent years. The ECB system modulates multiple functions, and drugs enhancing ECB signaling have shown promise as potential therapeutic agents in stress effects and other psychiatric and medical conditions. In this review, we focus on the interaction between the ECB-HPA systems in animal models for PTSD and in patients with PTSD. We summarize evidence supporting the use of cannabinoids in preventing and treating PTSD in preclinical and clinical studies. As the HPA system plays a key role in the mediation of the stress response and the pathophysiology of PTSD, we describe preclinical studies suggesting that enhancing ECB signaling is consistent with decreasing PTSD symptoms and dysfunction of the HPA axis. Overall, we suggest that a pharmacological treatment targeted at one system (e.g., HPA) may not be very effective because of the heterogeneity of the disorder. There are abnormalities across different neurotransmitter systems in the pathophysiology of PTSD and none of these systems function uniformly among all patients with PTSD. Hence, conceptually, enhancing ECB signaling may be a more effective avenue for pharmacological treatment.

Extent of cortisol suppression at baseline predicts improvement in HPA axis function during antidepressant treatment

BACKGROUND

A dysregulation in the hypothalamic-pituitary-adrenal (HPA)-axis function has been repeatedly observed in major depressive disorders (MDD). Normalization of this dysregulation, i.e. of cortisol suppression after glucocorticoid receptor (GR)-stimulation, may be mandatory for clinical remission in some patient subgroups. However, there are no biological measures applied in the clinical setting to identify patient subgroups with HPA axis alterations.

OBJECTIVE

We aimed to define a suppression index of cortisol concentrations before and after GR stimulation with dexamethasone to predict the variability in improvement of HPA axis activity during antidepressant treatment.

METHODS

A modified dexamethasone suppression test (mDST) was performed with blood withdrawal for cortisol and ACTH measurement before and 3 h after 1.5 mg dexamethasone intake at 18:00 in two cohorts of depressed patients treated in a naturalistic setting. The discovery sample consisted of 106 patients, the replication sample of 117 patients. The suppression index was defined as cCORTpreDEXcCORTpostDEX.

RESULTS

The baseline suppression index explained 27.4 % of the variance in changes of HPA axis activity before and after treatment with antidepressants. Age, cCORTpreDEXcACTHpreDEX at baseline and sex explained further variance up to 56.2 % (stepwise linear regression, p = 7.8e^-8). A threshold of the suppression index at baseline was determined by ROC analysis and revealed, that only patients with a maximum index of 2.32 achieved a normalization of the HPA axis activity after antidepressant treatment. In the replication sample, the threshold was 2.86. However, the estimated suppression index was not associated with treatment response.

CONCLUSION

For the first time, by establishing a short-term suppression index of cortisol before and after GR-stimulation a threshold could be identified to predict improvement of HPA axis activity during antidepressant therapy. After replication in further studies this index may help to identify patients who benefit from a specific treatment that targets components of the HPA axis in the future.

FAAH genotype, CRFR1 genotype, and cortisol interact to predict anxiety in an aging, rural Hispanic population: A Project FRONTIER study

The neurophysiological underpinnings involved in susceptibility to and maintenance of anxiety are not entirely known. However, two stress-responsive systems, the hypothalamic-pituitary-adrenal axis and the endocannabinoid system, may interact in anxiety. Here, we examine the relationship between FAAH genotype, CRFR1 genotype, baseline cortisol, and state anxiety in a rural adult population using data from Project FRONTIER. We predicted that FAAH A (AA and AC vs CC; rs324420) and three CRFR1 SNP minor alleles (rs7209436 C→ T [minor allele]; rs110402, G → A [minor]; and rs242924 G→ T [minor]), would interact to predict low baseline cortisol and low state anxiety scores. We found partial support for our prediction. In CRFR1 minor carriers, the FAAH AA or AC (vs. CC) genotype was associated with higher cortisol and with lower anxiety. In CRFR1 non-minors, those with FAAH AA or AC (vs. CC) showed decreased cortisol and higher anxiety. These results suggest that FAAH CC genotype only conveys risk for anxiety in individuals who are also carriers of the CRFR1 minor combination. FAAH genotype was significantly associated with baseline cortisol but was not independently associated with anxiety. Contrary to our predictions, baseline cortisol was negatively associated with anxiety. Lastly, we did not find any independent relationships between any of our SNPs and baseline cortisol or anxiety. These data suggest FAAH and cortisol interact to predict state anxiety, but that the relationship depends on CRFR1 genotype. The Project FRONTIER dataset is supported by Texas Tech University Health Sciences Center Garrison Institute on Aging.

A systematic meta-review of predictors of antidepressant treatment outcome in major depressive disorder

INTRODUCTION

The heterogeneity of symptoms and complex etiology of depression pose a significant challenge to the personalization of treatment. Meanwhile, the current application of generic treatment approaches to patients with vastly differing biological and clinical profiles is far from optimal. Here, we conduct a meta-review to identify predictors of response to antidepressant therapy in order to select robust input features for machine learning models of treatment response. These machine learning models will allow us to learn associations between patient features and treatment response which have predictive value at the individual patient level; this learning can be optimized by selecting high-quality input features for the model. While current research is difficult to directly apply to the clinic, machine learning models built using knowledge gleaned from current research may become useful clinical tools.

METHODS

The EMBASE and MEDLINE/PubMed online databases were searched from January 1996 to August 2017, using a combination of MeSH terms and keywords to identify relevant literature reviews. We identified a total of 1909 articles, wherein 199 articles met our inclusion criteria.

RESULTS

An array of genetic, immune, endocrine, neuroimaging, sociodemographic, and symptom-based predictors of treatment response were extracted, varying widely in clinical utility.

LIMITATIONS

Due to heterogeneous sample sizes, effect sizes, publication biases, and methodological disparities across reviews, we could not accurately assess the strength and directionality of every predictor.

CONCLUSION

Notwithstanding our cautious interpretation of the results, we have identified a multitude of predictors that can be used to formulate a priori hypotheses regarding the input features for a computational model. We highlight the importance of large-scale research initiatives and clinically accessible biomarkers, as well as the need for replication studies of current findings. In addition, we provide recommendations for future improvement and standardization of research efforts in this field.

Depression as a Neuroendocrine Disorder: Emerging Neuropsychopharmacological Approaches beyond Monoamines

Depression is currently recognized as a crucial problem in everyday clinical practice, in light of ever-increasing rates of prevalence, as well as disability, morbidity, and mortality related to this disorder. Currently available antidepressant drugs are notoriously problematic, with suboptimal remission rates and troubling side-effect profiles. Their mechanisms of action focus on the monoamine hypothesis for depression, which centers on the disruption of serotonergic, noradrenergic, and dopaminergic neurotransmission in the brain. Nevertheless, views on the pathophysiology of depression have evolved notably, and the comprehension of depression as a complex neuroendocrine disorder with important systemic implications has sparked interest in a myriad of novel neuropsychopharmacological approaches. Innovative pharmacological targets beyond monoamines include glutamatergic and GABAergic neurotransmission, brain-derived neurotrophic factor, various endocrine axes, as well as several neurosteroids, neuropeptides, opioids, endocannabinoids and endovanilloids. This review summarizes current knowledge on these pharmacological targets and their potential utility in the clinical management of depression.

An observational study of duloxetine versus SSRI monotherapy in Japanese patients with major depressive disorder: subgroup analyses of treatment effectiveness for pain, depressive symptoms, and quality of life

OBJECTIVE

To examine how clinical and demographic patient baseline characteristics influence effectiveness of duloxetine versus selective serotonin reuptake inhibitor (SSRI) treatment, in real-world Japanese clinical settings of patients with major depressive disorder (MDD) and associated painful physical symptoms (PPS).

METHODS

This was a multicenter, 12-week, prospective, observational study in patients with MDD (Quick Inventory of Depressive Symptomatology ≥16) and at least moderate PPS (Brief Pain Inventory-Short Form [BPI-SF] average pain ≥3). Patients received duloxetine or SSRIs (escitalopram, sertraline, paroxetine, or fluvoxamine). Assessments were made by using BPI-SF average pain, 17-item Hamilton Rating Scale for Depression (HAM-D17), EuroQol 5-dimension questionnaire, Social Adaptation Self-Evaluation Scale, Global Assessment of Functioning, and ability to work. Predefined subgroups included the number of previous episodes of depression (0 vs ≥1), baseline BPI-SF average pain score (≤6 vs >6), baseline HAM-D17 total score (≤18 vs >18), baseline HAM-D17 retardation (≤7 vs >7) and anxiety somatic subscale scores (≤6 vs >6), and age (<65 vs ≥65 years).

RESULTS

Treatment effectiveness was evaluated in 523 patients (duloxetine N=273, SSRIs N=250). Treatment with duloxetine was superior to SSRIs on most outcome measures in patients experiencing their first depressive episode, those with higher baseline PPS levels, and in patients with more severe baseline depression. This was also the case for older patients. In patients with less severe depression, SSRI treatment tended to show more improvements in depression and quality of life measures versus duloxetine treatment.

CONCLUSION

These preplanned subgroup analyses of data from a prospective observational study suggest that, for Japanese MDD patients with PPS, duloxetine is more effective than SSRIs in patients with a first episode of MDD, with more severe depression, or more severe PPS.

Oxidative stress: a potential link between emotional wellbeing and immune response

Emotional wellbeing is central to normal health and good living. Persistent psychological stress often disrupts emotional wellbeing and triggers onset of neuropsychiatric ailments. An integrated, multisystemic stress response involving neuroinflammatory, neuroendocrine and metabolic cascades seem to have some causative links. Of particular interest are the neuroinflammatory processes. Psychological stress has been suggested to negatively affect normal functioning of the immune system contributing to the pathophysiology of some neuropsychiatric conditions. Thus examination of the interaction between the immune system and the central nervous system is likely to reveal molecular targets critical for development of potential therapeutic and preventive measures. This review is a summarized discussion of evidence linking impact of psychological stress on the immune system, with a particular emphasis on oxidative stress mechanisms by which mental stress potentially impacts immune function leading to activation of multiple cascades resulting in subsequent manifestation of psychiatric symptomologies.

Crosstalk between endocannabinoid and immune systems: a potential dysregulation in depression?

BACKGROUND

The endocannabinoid (eCB) system, an endogenous lipid signaling system, appears to be dysregulated in depression. The role of endocannabinoids (eCBs) as potent immunomodulators, together with the accumulating support for a chronic low-grade inflammatory profile in depression, suggests a compelling hypothesis for a fundamental impairment in their intercommunication, in depression.

OBJECTIVE

We aim to review previous literature on individual associations between the immune and eCB systems and depression. It will focus on peripheral and central mechanisms of crosstalk between the eCB and immune systems. A potential dysregulation in this crosstalk will be discussed in the context of depression.

RESULTS

Investigations largely report a hypoactivity of the eCB system and increased inflammatory markers in individuals with depression. Findings depict a multifaceted communication whereby immunocompetent and eCB-related cells can both influence the suppression and enhancement of the other's activity in both the periphery and central nervous system. A dysregulation of the eCB system, as seen in depression, appears to be associated with central and peripheral concentrations of inflammatory agents implicated in the pathophysiology of this illness.

CONCLUSION

The eCB and immune systems have been individually associated with and implicated in pathogenic mechanisms of depression. Both systems tightly regulate the other's activity. As such, a dysregulation in this crosstalk has potential to influence the onset and maintenance of this neuropsychiatric illness. However, few studies have investigated both systems and depression conjointly. This review highlights the demand to consider joint eCB-immune interactions in the pathoetiology of depression.

For whom the endocannabinoid tolls: Modulation of innate immune function and implications for psychiatric disorders

Toll-like receptors (TLRs) mediate the innate immune response to pathogens and are critical in the host defence, homeostasis and response to injury. However, uncontrolled and aberrant TLR activation can elicit potent effects on neurotransmission and neurodegenerative cascades and has been proposed to trigger the onset of certain neurodegenerative disorders and elicit detrimental effects on the progression and outcome of established disease. Over the past decade, there has been increasing evidence demonstrating that the endocannabinoid system can elicit potent modulatory effects on inflammatory processes, with clinical and preclinical evidence demonstrating beneficial effects on disease severity and symptoms in several inflammatory conditions. This review examines the evidence supporting a modulatory effect of endocannabinoids on TLR-mediated immune responses both peripherally and centrally, and the implications for psychiatric disorders such as depression and schizophrenia.

Genetic variation in IL-1β, IL-2, IL-6, TSPO and BDNF and response to duloxetine or placebo treatment in major depressive disorder

AIM

This study investigated polymorphisms of five inflammatory-related genes for association with duloxetine and placebo response in patients with major depression.

PATIENTS & METHODS

Twenty SNPs in IL-1β, IL-2, IL-6, TSPO and BDNF were genotyped in major depressive disorder patients treated with either duloxetine (n = 215) or placebo (n = 235) for up to 8 weeks. Treatment response was measured with the Montgomery-Åsberg Depression Rating Scale.

RESULTS

IL-6 variants rs2066992 and rs10242595 were nominally associated with response to duloxetine (p = 0.047 and p = 0.028, respectively). Notably, the variant rs2066992 was also associated with placebo response (p = 0.026). However, none of our results remained significant after correction for multiple testing.

CONCLUSION

Our findings tentatively suggest that IL-6 variants play a role in duloxetine and placebo response, which warrants further investigation.

High Times for Painful Blues: The Endocannabinoid System in Pain-Depression Comorbidity

Depression and pain are two of the most debilitating disorders worldwide and have an estimated cooccurrence of up to 80%. Comorbidity of these disorders is more difficult to treat, associated with significant disability and impaired health-related quality of life than either condition alone, resulting in enormous social and economic cost. Several neural substrates have been identified as potential mediators in the association between depression and pain, including neuroanatomical reorganization, monoamine and neurotrophin depletion, dysregulation of the hypothalamo-pituitary-adrenal axis, and neuroinflammation. However, the past decade has seen mounting evidence supporting a role for the endogenous cannabinoid (endocannabinoid) system in affective and nociceptive processing, and thus, alterations in this system may play a key role in reciprocal interactions between depression and pain. This review will provide an overview of the preclinical evidence supporting an interaction between depression and pain and the evidence supporting a role for the endocannabinoid system in this interaction.

Drug discovery strategies that focus on the endocannabinoid signaling system in psychiatric disease

INTRODUCTION

The endocannabinoid (eCB) system plays an important role in the control of mood, and its dysregulation has been implicated in several psychiatric disorders. Targeting the eCB system appears to represent an attractive and novel approach to the treatment of depression and other mood disorders. However, several failed clinical trials have diminished enthusiasm for the continued development of eCB-targeted therapeutics for psychiatric disorders, despite the encouraging preclinical data and promising preliminary results obtained with the synthetic cannabinoid nabilone for treating post-traumatic stress disorder.

AREAS COVERED

This review describes the eCB system's role in modulating cell signaling within the brain. There is a specific focus on eCB's regulation of monoamine neurotransmission and the stress axis, as well as how dysfunction of this interaction can contribute to the development of psychiatric disorders. Additionally, the review provides discussion on compounds and drugs that target this system and might prove to be successful for the treatment of mood-related psychiatric disorders.

EXPERT OPINION

The discovery of increasingly selective modulators of CB receptors should enable the identification of optimal therapeutic strategies. It should also maximize the likelihood of developing safe and effective treatments for debilitating psychiatric disorders.