HPA axis and aging in depression: systematic review and meta-analysis

"Inflamed" depression: A review of the interactions between depression and inflammation and current anti-inflammatory strategies for depression

Depression is a common mental disorder, the effective treatment of which remains a challenging issue worldwide. The clinical pathogenesis of depression has been deeply explored, leading to the formulation of various pathogenic hypotheses. Among these, the monoamine neurotransmitter hypothesis holds a prominent position, yet it has significant limitations as more than one-third of patients do not respond to conventional treatments targeting monoamine transmission disturbances. Over the past few decades, a growing body of research has highlighted the link between inflammation and depression as a potential key factor in the pathophysiology of depression. In this review, we first summarize the relationship between inflammation and depression, with a focus on the pathophysiological changes mediated by inflammation in depression. The mechanisms linking inflammation to depression as well as multiple anti-inflammatory strategies are also discussed, and their efficacy and safety are assessed. This review broadens the perspective on specific aspects of using anti-inflammatory strategies for treating depression, laying the groundwork for advancing precision medicine for individuals suffering from "inflamed" depression.

From movement to motivation: a proposed framework to understand the antidepressant effect of exercise

Depression is the leading cause of disability worldwide, exerting a profound negative impact on quality of life in those who experience it. Depression is associated with disruptions to several closely related neural and cognitive processes, including dopamine transmission, fronto-striatal brain activity and connectivity, reward processing and motivation. Physical activity, especially aerobic exercise, reduces depressive symptoms, but the mechanisms driving its antidepressant effects are poorly understood. Here we propose a novel hypothesis for understanding the antidepressant effects of exercise, centred on motivation, across different levels of explanation. There is robust evidence that aerobic exercise decreases systemic inflammation. Inflammation is known to reduce dopamine transmission, which in turn is strongly implicated in effort-based decision making for reward. Drawing on a broad range of research in humans and animals, we propose that by reducing inflammation and boosting dopamine transmission, with consequent effects on effort-based decision making for reward, exercise initially specifically improves 'interest-activity' symptoms of depression-namely anhedonia, fatigue and subjective cognitive impairment - by increasing propensity to exert effort. Extending this framework to the topic of cognitive control, we explain how cognitive impairment in depression may also be conceptualised through an effort-based decision-making framework, which may help to explain the impact of exercise on cognitive impairment. Understanding the mechanisms underlying the antidepressant effects of exercise could inform the development of novel intervention strategies, in particular personalised interventions and boost social prescribing.

Depressive symptoms were associated with an elevated prevalence of gallstones among adults in the United States: A cross-sectional analysis of NHANES 2017-2020

Background

 Gallstone disease is one of the most common gastrointestinal disorders. Despite extensive research exploring the risk factors associated with gallstones, the association between depressive symptoms and gallstones remains inadequately understood. This study aimed to assess the association between depressive symptoms and the prevalence of gallstones among adults in the United States.

Methods

In this study, a cross-sectional design utilized data from the National Health and Nutrition Examination Survey (NHANES) spanning the years 2017 to 2020. The assessment of depressive symptoms was conducted through the utilization of the Patient Health Questionnaire-9 (PHQ-9), which assigns total scores ranging from 0 to 27. Participants with PHQ-9 scores equal to or exceeding 10 were categorized as having clinically relevant depressive symptoms. Multivariable adjusted logistic regression and subgroup analysis were used to assess the association between depressive symptoms and gallstone prevalence.

Results

A total of 7,797 participants aged 20 years or older were enrolled in this study, of whom 835 had a self-reported history of gallstones. After multiple adjustments, each one-point increase in PHQ-9 scores was associated with a 5 % increase in the risk of gallstones (odds ratio [OR], 1.05; 95 % confidence interval [CI], 1.03, 1.07, P < 0.001). Compared to individuals with PHQ-9 scores < 10, participants with PHQ-9 total scores ≥ 10 exhibited a 79 % higher risk of gallstones (OR = 1.79, 95 % CI: 1.43, 2.23, P < 0.001).

Conclusion

Depressive symptoms were associated with an elevated prevalence of gallstones. However, it is important to note that further validation through prospective cohort studies is warranted to confirm this finding.

Bidirectional Associations of Depressive Symptoms and Cognitive Function Over Time

Importance

Cognitive decline and depressive symptoms often co-occur among older adults, and they share several mechanisms. Despite the fact that cognitive dysfunction has been linked to increased depressive symptoms, the directionality of this association remains unclear.

Objective

To examine whether there is a bidirectional association between depressive symptoms and cognitive function in English adults aged 50 years or older throughout a 16-year follow-up period.

Design, Setting, and Participants

This cohort study included a nationally representative sample of community-dwelling English adults aged 50 years or older. The current analysis included 8268 eligible participants with relevant data. These participants were examined every other year from 2002 and 2003 until 2018 and 2019, resulting in a follow-up period of up to 16 years. Data were analyzed from July to November 2023.

Main Outcomes and Measures

The bivariate dual change score models were used to estimate the multivariable associations between depressive symptoms and cognitive function, which were interchangeably used as exposures and outcomes. Cognitive measures include memory and verbal fluency tests, while the Center for Epidemiologic Studies Depression Scale evaluated depressive symptoms.

Results

The study population of 8268 participants had a mean (SD) age of 64 (10) years at the study baseline, and 4517 participants (55%) were female. Higher depressive symptoms were cross-sectionally associated with poorer memory (β intercept, -0.018; standard error [SE], 0.004; P < .001) and verbal fluency (β intercept, -0.009; SE, 0.004; P = .02) at study baseline. A steeper linear change in depressive symptoms was associated with an accelerated memory change (β intercept, -0.253; SE, 0.079; P = .001), and a linear change in memory was associated with an acceleration in depressive symptoms over time (β intercept, 0.016; SE, 0.006; P = .005). This bidirectional change was not observed with verbal fluency.

Conclusions and Relevance

In this study, greater depressive symptoms were associated with poorer memory at the study baseline and steeper memory change over time. A gradual linear change in depressive symptoms contributed to accelerated memory loss and vice versa, suggesting that psychological mood and memory performance are intrinsically associated.

Depression and dental caries in US adults, NHANES 2015-2018

PURPOSE

This study aimed to investigate the link between depression and untreated dental caries among adults in the United States.

METHODS

Data were collected from the National Health and Nutrition Survey (2015-2018); respondents aged 20 years or older who completed a patient health questionnaire and underwent a comprehensive oral examination were included. Participants were categorized into three groups according to depressive symptoms as follows: those with no, mild, or moderate to severe depression. Data were weighted, and multiple potential covariates were included in the analysis to provide national estimates and account for the complex sample design. A multivariable weighted logistic regression model was performed to test the hypothesis that varying degrees of depression in American adults are associated with untreated dental caries. Subgroup analyses were performed based on age and gender after adjusting for potential covariates. A P value of <.05 was considered significant.

RESULTS

Among 8740 participants, the prevalence of untreated coronal and root caries was 20.50% and 12.92%, respectively. Moderate to severe depression was a significant risk factor (odds ratio, 1.25; 95% confidence interval, 1.09-1.66) for untreated root caries. The risk of untreated root caries increased by 87% in young adults (aged 20-44 years) and by 46% in women with moderate to severe depression. The suest analysis revealed that the impact of moderate to severe depressive disorder on untreated root caries was non-significantly different between the age subgroup (p=0.09) and sex subgroup (p=0.51). However, depression was non-significantly associated with untreated coronal caries (mild depression: OR, 1.07; 95% CI, 0.85-1.34; moderate to severe depression 1.06; 95% CI, 0.83-1.36; respectively).

CONCLUSION

The results of this study suggested a significant association between moderate and severe depression and untreated root caries; however, the association with untreated coronal caries was non-significant. In the United States, moderate and severe depression in adults is associated with root caries.

Implications of Kynurenine Pathway Metabolism for the Immune System, Hypothalamic-Pituitary-Adrenal Axis, and Neurotransmission in Alcohol Use Disorder

In recent years, there has been a marked increase in interest in the role of the kynurenine pathway (KP) in mechanisms associated with addictive behavior. Numerous reports implicate KP metabolism in influencing the immune system, hypothalamic-pituitary-adrenal (HPA) axis, and neurotransmission, which underlie the behavioral patterns characteristic of addiction. An in-depth analysis of the results of these new studies highlights interesting patterns of relationships, and approaching alcohol use disorder (AUD) from a broader neuroendocrine-immune system perspective may be crucial to better understanding this complex phenomenon. In this review, we provide an up-to-date summary of information indicating the relationship between AUD and the KP, both in terms of changes in the activity of this pathway and modulation of this pathway as a possible pharmacological approach for the treatment of AUD.

The Role of Palliative Care in Cardiovascular Disease

The American Heart Association has recommended that palliative care be integrated into the care of all patients with advanced cardiac illnesses. Notwithstanding, the number of patients receiving specialist palliative intervention worldwide remains extremely small. This review examines the nature of palliative care and what is known about its delivery to patients with cardiac illness. Most of the published literature on the subject concern advanced heart failure; however, some data also exist regarding patients with heart transplantation, pulmonary hypertension, valvular disease, congenital heart disease, indwelling devices, mechanical circulatory support, and advanced coronary disease. In addition, outcome data, certification requirements, workforce challenges, barriers to implementation, and a potential caveat about palliative care will also be examined. Further work is required regarding appropriate means of implementation, quality control, and timing of intervention.

Glucocorticoids, their uses, sexual dimorphisms, and diseases: new concepts, mechanisms, and discoveries

The normal stress response in humans is governed by the hypothalamic-pituitary-adrenal (HPA) axis through heightened mechanisms during stress, raising blood levels of the glucocorticoid hormone cortisol. Glucocorticoids are quintessential compounds that balance the proper functioning of numerous systems in the mammalian body. They are also generated synthetically and are the preeminent therapy for inflammatory diseases. They act by binding to the nuclear receptor transcription factor glucocorticoid receptor (GR), which has two main isoforms (GRα and GRβ). Our classical understanding of glucocorticoid signaling is from the GRα isoform, which binds the hormone, whereas GRβ has no known ligands. With glucocorticoids being involved in many physiological and cellular processes, even small disruptions in their release via the HPA axis, or changes in GR isoform expression, can have dire ramifications on health. Long-term chronic glucocorticoid therapy can lead to a glucocorticoid-resistant state, and we deliberate how this impacts disease treatment. Chronic glucocorticoid treatment can lead to noticeable side effects such as weight gain, adiposity, diabetes, and others that we discuss in detail. There are sexually dimorphic responses to glucocorticoids, and women tend to have a more hyperresponsive HPA axis than men. This review summarizes our understanding of glucocorticoids and critically analyzes the GR isoforms and their beneficial and deleterious mechanisms and the sexual differences that cause a dichotomy in responses. We also discuss the future of glucocorticoid therapy and propose a new concept of dual GR isoform agonist and postulate why activating both isoforms may prevent glucocorticoid resistance.

Sex differences in cortisol levels in depression: A systematic review and meta-analysis

Higher prevalence of depression in females might be associated with sex-specific cortisol levels. Evidence exists that cortisol levels differ between healthy females and males, however a sex-specific association in depression has not been systematically assessed. Thus, the current study quantifies the existing literature on different cortisol parameters, i.e., basal cortisol, hair cortisol, cortisol awakening response (CAR), and cortisol stress reactivity comparing depressed females and males as well as sex-specific comparisons with healthy controls. Following an extensive literature research, fifty original articles were included. Depressed females had significantly higher hair cortisol, higher CAR, and lower cortisol stress reactivity compared to depressed males. In comparison with sex-matched controls, female patients had significantly higher evening basal cortisol, higher CAR and lower cortisol stress reactivity, and male patients had significantly higher general, morning and evening basal cortisol. Overall, sex as a fundamental driver of cortisol levels in depression needs to be taken into account.

Depression, Cancer, Inflammation, and Endogenous Opioids: Pathogenic Relationships and Therapeutic Options

Endogenous opioids and their associated receptors form a system that maintains survival by positively reinforcing behaviors that are vital to life. Cancer and cancer treatment side effects capitalize on this system pathogenically, leading to maladaptive biological responses (e.g., inflammation), as well as cognitive and emotional consequences, most notably depression. Psychologists who treat people with cancer frequently find depression to be a primary target for intervention. However, in people with cancer, the etiology of depression is unique and complex. This complexity necessitates that psycho-oncologists have a fundamental working knowledge of the biological substrates that underlie depression/cancer comorbidity. Building on other chapters in this volume pertaining to cancer and endogenous opioids, this chapter focuses on the clinical applications of basic scientific findings.

Abdominal obesity mediates the causal relationship between depression and the risk of gallstone disease: retrospective cohort study and Mendelian randomization analyses

OBJECTIVE

Our study aimed to explore the causal effect of depression on the risk of gallstone disease, and the mediation effects of metabolic traits.

METHODS

A retrospective cohort study on Chinese elderly from the Dongfeng-Tongji cohort (including 18,141 individuals) was conducted to estimate the adverse effect of probable depression on the risk of gallstone disease. Two-sample Mendelian randomization was performed in European and East-Asian ancestries, to verify the causal relationship between major depression and gallstone disease. We further applied two-step Mendelian randomization to explore the mediation effects of metabolic traits.

RESULTS

In the cohort study, probable depression was associated with an increased risk of gallstone disease within 5 years, with RR (95% CI) of 1.33 (1.12, 1.58) in multivariable regression, and 1.34 (1.11, 1.61) following propensity score weighting. Bidirectional Mendelian randomization in European ancestry revealed a positive causal effect (OR: 1.21; 95% CI: 1.07 to 1.37) of genetically predicted major depression liability on gallstone disease, based on the inverse variance weighted method. Little evidence was presented from other complementary approaches, and the analysis in East-Asian ancestry (IVW estimated OR: 1.03; 95% CI: 0.92 to 1.15). The indirect effect via waist circumference and HDL-C were 1.06 (95% CI: 1.02 to 1.10) and 1.01 (95% CI: 1.00 to 1.01) respectively, which mediated 25.8% and 3.78% of the causal relationship.

CONCLUSIONS

Our study suggested a higher risk of gallstone disease in the population with probable depression, while the two-sample Mendelian randomization provided weak evidence for the causal relationship, which was moderately mediated by abdominal obesity.

Cherry leaf decoction inhibits NMDAR expression and thereby ameliorates CUMS- induced depression-like behaviors through downregulation of α2δ-1

Depression is a complex and prevalent mental illness. Cherry leaf is a traditional Chinese herbal medicine, which has confirmed to exert a certain antidepressant effect, but its potential neural regulation mechanism is not clear. This paper aims to investigate the improved action of cherry leaf decoction (CLD) on chronic unpredictable mild stress (CUMS) rats and its potential neural regulation mechanism by verifying the role and function of NMDAR regulatory target α2δ-1 in depression due to CUMS. Male SD rats were subjected to random stressors persisting for 5 weeks to establish the CUMS depression rat model. CLD could effectively alleviate depression-like behaviors of CUMS rats in behavioral tests including sucrose preference test, forced swimming test, tail suspension test and open field test. After the administration of the CLD, the expression of corticotropic-releasing hormone (CRH) in the hypothalamus was inhibited. Moreover, the levels of CRH, adrenal cortical hormone (ACTH) and corticosterone (CORT) in serum also decreased significantly. CUMS upregulated the expressions of α2δ-1, N-methyl-d-aspartate receptor 1 (NR1), NR2A and NR2B, and enhanced the binding ability to of α2δ-1 and NR1, which were reversed by CLD. The results demonstrated that CLD could ameliorate depression-like behaviors due to CUMS, which was related to the fact that CLD down-regulated α2δ-1 level and interfered with α2δ-1 binding to NR1, thereby reducing NMDAR expression and ultimately inhibiting HPA axis activity.

Fluoxetine combined with swimming exercise synergistically reduces lipopolysaccharide-induced depressive-like behavior by normalizing the HPA axis and brain inflammation in mice

Major depression disorder is a debilitating psychiatric disease affecting millions of people worldwide. This disorder is the leading cause of morbidity and mortality in high-income countries. Selective serotonin reuptake inhibitors such as fluoxetine are first-line drugs for treating depression-related disorders, but not all patients respond well to these antidepressants. This study aimed to evaluate whether fluoxetine combined with aerobic exercise can affect lipopolysaccharide (LPS)-induced depressive-like behavior, hypothalamic-pituitary-adrenal (HPA) axis dysregulation, and brain inflammation in mice. Male mice were exposed to fluoxetine, swimming exercise, or a combination of both and finally treated with LPS. We measured depression-related symptoms such as anhedonia, behavioral despair, weight gain, and food intake. Hormones (corticosterone and testosterone) and cytokines (IL-1β, IL-6, TNF-α, IL-10) were also measured in serum and brain (hippocampus and prefrontal cortex), respectively. The findings indicated that LPS induced anhedonia and behavioral despair and increased corticosterone, hippocampal IL-1β, TNF-α, and decreased testosterone and hippocampal IL-10 in mice. Fluoxetine and exercise separately reduced LPS-induced depressive-like behavior, while their combination synergistically reduced these symptoms in LPS-treated mice. We found fluoxetine alone increased food intake and body weight in LPS-treated mice. Fluoxetine and exercise combination reduced corticosterone, hippocampal TNF-α, and prefrontal IL-6 and TNF-α levels and increased testosterone and hippocampal and prefrontal IL-10 levels more effectively than fluoxetine alone in LPS-treated mice. This study suggests that swimming exercise combined with fluoxetine can affect depression-related behavior, HPA axis, and brain inflammation more effectively than when they are used separately.

Exploring the relationship between depression and multimorbidity in Chinese middle-aged and older people based on propensity score matching

BACKGROUND

This study aimed to explore the relationship between depression and multimorbidity among middle-aged and older people in China.

METHODS

The cross-sectional study used the 2018 China Longitudinal Study of Health and Retirement and included a sample of 19,761 middle-aged and older adults aged 45 years and above. Propensity score matching was used to match samples of individuals with and without depression symptoms. The association between depression symptoms and multimorbidity and dose-response relationships were analyzed using logistic regression and restricted cubic spline (RCS) models for matched samples.

RESULTS

Logistic regression analysis showed that the prevalence of multimorbidity was 1.49 times higher among middle-aged and older adults in the depression symptom group compared to the non-depression group (95% CI:1.24, 1.80). The RCS curves for the relationship between depression and multimorbidity showed an overall increasing trend (P = 0.028). And prevalence of arthritis and digestive disease in the depressed and non-depressed groups is 3.6% and 3.9%, respectively.

LIMITATIONS

It was difficult to draw conclusions about causation since the study was cross-sectional, and CESD-10 scores do not represent the population study finally diagnosed with depression, the conclusions should be promoted with caution.

CONCLUSIONS

Middle-aged and older people with depressive symptoms are more likely to have multimorbidity than non-depressed individuals. Furthermore, the likelihood of multimorbidity increases with higher depression scores, and the binary combinations were similarly distributed. Therefore, attention should be paid to the management of mental health in the middle-aged and older adult population to alleviate and prevent any mental health issues they might face.

Comorbidity between major depressive disorder and physical diseases: a comprehensive review of epidemiology, mechanisms and management

Populations with common physical diseases - such as cardiovascular diseases, cancer and neurodegenerative disorders - experience substantially higher rates of major depressive disorder (MDD) than the general population. On the other hand, people living with MDD have a greater risk for many physical diseases. This high level of comorbidity is associated with worse outcomes, reduced adherence to treatment, increased mortality, and greater health care utilization and costs. Comorbidity can also result in a range of clinical challenges, such as a more complicated therapeutic alliance, issues pertaining to adaptive health behaviors, drug-drug interactions and adverse events induced by medications used for physical and mental disorders. Potential explanations for the high prevalence of the above comorbidity involve shared genetic and biological pathways. These latter include inflammation, the gut microbiome, mitochondrial function and energy metabolism, hypothalamic-pituitary-adrenal axis dysregulation, and brain structure and function. Furthermore, MDD and physical diseases have in common several antecedents related to social factors (e.g., socioeconomic status), lifestyle variables (e.g., physical activity, diet, sleep), and stressful live events (e.g., childhood trauma). Pharmacotherapies and psychotherapies are effective treatments for comorbid MDD, and the introduction of lifestyle interventions as well as collaborative care models and digital technologies provide promising strategies for improving management. This paper aims to provide a detailed overview of the epidemiology of the comorbidity of MDD and specific physical diseases, including prevalence and bidirectional risk; of shared biological pathways potentially implicated in the pathogenesis of MDD and common physical diseases; of socio-environmental factors that serve as both shared risk and protective factors; and of management of MDD and physical diseases, including prevention and treatment. We conclude with future directions and emerging research related to optimal care of people with comorbid MDD and physical diseases.

The Effects of Chronic Unpredictable Mild Stress and Semi-Pure Diets on the Brain, Gut and Adrenal Medulla in C57BL6 Mice

Chronic stress is known to perturb serotonergic regulation in the brain, leading to mood, learning and memory impairments and increasing the risk of developing mood disorders. The influence of the gut microbiota on serotonergic regulation in the brain has received increased attention recently, justifying the investigation of the role of diet on the gut and the brain in mood disorders. Here, using a 4-week chronic unpredictable mild stress (CUMS) model in mice, we aimed to investigate the effects of a high-fat high-glycaemic index (HFD) and high-fibre fruit & vegetable "superfood" (SUP) modifications of a semi-pure AIN93M diet on behaviour, serotonin synthesis and metabolism pathway regulation in the brain and the gut, as well as the gut microbiota and the peripheral adrenal medullary system. CUMS induced anxiety-like behaviour, dysregulated the tryptophan and serotonin metabolic pathways in the hippocampus, prefrontal cortex, and colon, and altered the composition of the gut microbiota. CUMS reduced the catecholamine synthetic capacity of the adrenal glands. Differential effects were found in these parameters in the HFD and SUP diet. Thus, dietary modifications may profoundly affect the multiple dynamic systems involved in mood disorders.

Association between frailty and depression: A bidirectional Mendelian randomization study

Frailty and depression were linked in observational studies, but the causality remains ambiguous. We intended to explore it using Mendelian randomization (MR). We obtained frailty genome-wide association study (GWAS) data from UK Biobank and TwinGen meta-analysis, and depression GWAS data from Psychiatric Genomics Consortium (PGC) and FinnGen (respectively recorded as PD and FD). We performed univariable and multivariable-adjusted MR with adjustments for body mass index (BMI) and physical activity (PA). Frailty was significantly associated with elevated risks of PD (OR, 1.860; 95% CI, 1.439 to 2.405; P < 0.001) and FD (OR, 1.745; 95% CI, 1.193 to 2.552; P = 0.004), and depression was meanwhile a susceptible factor for frailty (PD: β, 0.146; 95% CI, 0.086 to 0.201; P < 0.001; and FD: β, 0.112; 95% CI, 0.051 to 0.174; P < 0.001). This association was robust after adjustments for BMI or PA. Our study provides evidence of the bidirectional causal association between frailty and depression from genetic perspectives.

Hippocampal Dynamic Functional Connectivity, HPA Axis Activity, and Personality Trait in Bipolar Disorder with Suicidal Attempt

INTRODUCTION

Suicide in bipolar disorder (BD) is a multifaceted behavior, involving specific neuroendocrine and psychological mechanisms. According to previous studies, we hypothesized that suicidal BD patients may exhibit impaired dynamic functional connectivity (dFC) variability of hippocampal subregions and hypothalamic-pituitary-adrenal (HPA) axis activity, which may be associated with suicide-related personality traits. The objective of our study was to clarify this.

METHODS

Resting-state functional magnetic resonance imaging data were obtained from 79 patients with BD, 39 with suicidal attempt (SA), and 40 without SA, and 35 healthy controls (HCs). The activity of the HPA axis was assessed by measuring morning plasma adrenocorticotropic hormone (ACTH) and cortisol (CORT) levels. All participants underwent personality assessment using Minnesota Multiphasic Personality Inventory-2 (MMPI-2).

RESULTS

BD patients with SA exhibited increased dFC variability between the right caudal hippocampus and the left superior temporal gyrus (STG) when compared with non-SA BD patients and HCs. BD with SA also showed significantly lower ACTH levels in comparison with HCs, which was positively correlated with increased dFC variability between the right caudal hippocampus and the left STG. BD with SA had significantly higher scores of Hypochondriasis, Depression, and Schizophrenia than non-SA BD. Additionally, multivariable regression analysis revealed the interaction of ACTH × dFC variability between the right caudal hippocampus and the left STG independently predicted MMPI-2 score (depression evaluation) in suicidal BD patients.

CONCLUSION

These results suggested that suicidal BD exhibited increased dFC variability of hippocampal-temporal cortex and less HPA axis hyperactivity, which may affect their personality traits.

Sex-related differences in the associations between diurnal cortisol pattern and social and emotional loneliness in older adults

Introduction

Loneliness is a distressful feeling that can affect mental and physical health, particularly among older adults. Cortisol, the primary hormone of the Hypothalamic-Pituitary-Adrenal axis (HPA-axis), may act as a biological transducer through which loneliness affects health. While most previous studies have evaluated the association between loneliness, as a unidimensional construct, and diurnal cortisol pattern, no research has examined this relationship discriminating between social and emotional loneliness in older adults. As sex differences in the negative mental health outcomes of loneliness have been reported, we also investigated whether diurnal cortisol indices and loneliness associations occur in a sex-specific manner.

Methods

We analyzed the diurnal cortisol- pattern in 142 community-dwelling, non-depressed, Caucasian older adults (55,6% female) aged 60-90. Social and emotional (family and romantic) loneliness scores were assessed using the Spanish version of the Social and Emotional Loneliness Scale for Adults (SELSA). Five salivary cortisol samples were used to capture key features of the diurnal cortisol pattern, including: awakening and bedtime cortisol levels, awakening response (CAR), post-awakening cortisol output (post-awakening cortisol [i.e., the area under the curve with reference to the ground: AUCG]), total diurnal cortisol release (AUCG), and diurnal cortisol slope (DCS).

Results

After controlling for sociodemographic variables, the hierarchical linear multiple regression analyses revealed that in male older adults, higher scores on social and family loneliness were associated with elevated awakening cortisol levels, total diurnal cortisol output, and a steeper diurnal cortisol slope (DCS). However, these associations were not observed in female older adults. In addition, feelings of romantic loneliness were positively associated with bedtime cortisol levels and AUCG in older males. Multilevel growth curve modeling showed that experiencing more social and emotional loneliness predicted higher diurnal cortisol output throughout the day in older male adults.

Discussion

The presence of sex differences in the relationship between cortisol indices and loneliness among older adults holds particular significance for diagnostic and screening procedures. Combining loneliness scales as screening tools with diurnal cortisol measures has the potential to be an effective and cost-efficient approach in identifying higher-risk individuals at early stages.

Biological Embedding of Early-Life Adversity and a Scoping Review of the Evidence for Intergenerational Epigenetic Transmission of Stress and Trauma in Humans

Severe or chronic stress and trauma can have a detrimental impact on health. Evidence suggests that early-life adversity can become biologically embedded and has the potential to influence health outcomes decades later. Epigenetics is one mechanism that has been implicated in these long-lasting effects. Observational studies in humans indicate that the effects of stress could even persist across generations, although whether or not epigenetic mechanisms are involved remains under debate. Here, we provide an overview of studies in animals and humans that demonstrate the effects of early-life stress on DNA methylation, one of the most widely studied epigenetic mechanisms, and summarize findings from animal models demonstrating the involvement of epigenetics in the transmission of stress across generations. We then describe the results of a scoping review to determine the extent to which the terms intergenerational or transgenerational have been used in human studies investigating the transmission of trauma and stress via epigenetic mechanisms. We end with a discussion of key areas for future research to advance understanding of the role of epigenetics in the legacy effects of stress and trauma.

The role of loneliness in the association between chronic physical illness and depressive symptoms among older adults: A prospective cohort study

BACKGROUND

Chronic physical illness increases the risk of subsequent depressive symptoms, but we know little about the mechanisms underlying this association that interventions can target. We investigated whether loneliness might explain associations between chronic illness and subsequent depressive symptoms.

METHODS

We used English Longitudinal Study of Ageing data, a prospective cohort of adults over 50. Our exposure was chronic illnesses (wave two) including arthritis, cancer, diabetes, cardiovascular disease, stroke, and chronic obstructive pulmonary disease. Loneliness scores were a mediator on the short University of California, Los Angeles Loneliness Scale at wave three. Depressive symptom scores (outcome) were measured using the Centre for Epidemiologic Studies Depression Scale (wave four). We examined associations of chronic physical illness with loneliness and depressive symptoms in univariable and multivariable regression models.

RESULTS

Fully-adjusted models included 2436 participants with the depression outcome and 2052 participants with the loneliness outcome. Chronic physical illness was associated with 21 % (incident rate ratio = 1.21, 95%CI = 1.03-1.42) higher depression scores at follow-up. We found no evidence of an association between chronic physical illness and loneliness and therefore did not proceed to analyses of mediation.

LIMITATIONS

More prevalent chronic illnesses could have driven our results, such as cardiovascular disease.

CONCLUSIONS

Chronic physical illnesses increase the risk of depressive symptoms in older adults. However, we did not find any that chronic physical illnesses were associated with an increased risk of subsequent loneliness. Therefore, interventions targeting loneliness to reduce depression in older adults with chronic physical illness may be insufficient.

Hypothalamus and Post-Traumatic Stress Disorder: A Review

Humans have lived in a dynamic environment fraught with potential dangers for thousands of years. While fear and stress were crucial for the survival of our ancestors, today, they are mostly considered harmful factors, threatening both our physical and mental health. Trauma is a highly stressful, often life-threatening event or a series of events, such as sexual assault, war, natural disasters, burns, and car accidents. Trauma can cause pathological metaplasticity, leading to long-lasting behavioral changes and impairing an individual's ability to cope with future challenges. If an individual is vulnerable, a tremendously traumatic event may result in post-traumatic stress disorder (PTSD). The hypothalamus is critical in initiating hormonal responses to stressful stimuli via the hypothalamic-pituitary-adrenal (HPA) axis. Linked to the prefrontal cortex and limbic structures, especially the amygdala and hippocampus, the hypothalamus acts as a central hub, integrating physiological aspects of the stress response. Consequently, the hypothalamic functions have been attributed to the pathophysiology of PTSD. However, apart from the well-known role of the HPA axis, the hypothalamus may also play different roles in the development of PTSD through other pathways, including the hypothalamic-pituitary-thyroid (HPT) and hypothalamic-pituitary-gonadal (HPG) axes, as well as by secreting growth hormone, prolactin, dopamine, and oxytocin. This review aims to summarize the current evidence regarding the neuroendocrine functions of the hypothalamus, which are correlated with the development of PTSD. A better understanding of the role of the hypothalamus in PTSD could help develop better treatments for this debilitating condition.

Lifetime discrimination, habitual and daily everyday discrimination, and diurnal cortisol among older African Americans adults

Experiences of discrimination can be major life events or daily chronic hassles that occur in various social contexts (e.g., housing, education, employment) and have been found to predict adverse health outcomes, including dysregulation of the Hypothalamic-Pituitary-Adrenal (HPA) axis. Previous work on daily cortisol dynamics has generally revealed an association between discrimination and flatter cortisol slopes, particularly among racial minorities. However, most of the existing studies have focused on youth and young adults, with little work among older adults. The current study aimed to investigate the relationship between three measures of discrimination (lifetime discrimination, habitual everyday discrimination, and daily everyday discrimination) and diurnal cortisol secretion in a sample of 203 older African Americans. Study results indicated that individuals reporting higher levels of lifetime discrimination experienced morning hypocortisolism and flatter diurnal cortisol slopes. Exploratory analyses also showed that prior daily everyday discrimination was significantly associated with blunted cortisol awakening response (CAR) the next day. Our findings underline the role of discrimination in modulating daily cortisol dynamics among older African American adults and advance knowledge on how social stressors influence healthy aging.

Biological factors influencing depression in later life: role of aging processes and treatment implications

Late-life depression occurring in older adults is common, recurrent, and malignant. It is characterized by affective symptoms, but also cognitive decline, medical comorbidity, and physical disability. This behavioral and cognitive presentation results from altered function of discrete functional brain networks and circuits. A wide range of factors across the lifespan contributes to fragility and vulnerability of those networks to dysfunction. In many cases, these factors occur earlier in life and contribute to adolescent or earlier adulthood depressive episodes, where the onset was related to adverse childhood events, maladaptive personality traits, reproductive events, or other factors. Other individuals exhibit a later-life onset characterized by medical comorbidity, pro-inflammatory processes, cerebrovascular disease, or developing neurodegenerative processes. These later-life processes may not only lead to vulnerability to the affective symptoms, but also contribute to the comorbid cognitive and physical symptoms. Importantly, repeated depressive episodes themselves may accelerate the aging process by shifting allostatic processes to dysfunctional states and increasing allostatic load through the hypothalamic-pituitary-adrenal axis and inflammatory processes. Over time, this may accelerate the path of biological aging, leading to greater brain atrophy, cognitive decline, and the development of physical decline and frailty. It is unclear whether successful treatment of depression and avoidance of recurrent episodes would shift biological aging processes back towards a more normative trajectory. However, current antidepressant treatments exhibit good efficacy for older adults, including pharmacotherapy, neuromodulation, and psychotherapy, with recent work in these areas providing new guidance on optimal treatment approaches. Moreover, there is a host of nonpharmacological treatment approaches being examined that take advantage of resiliency factors and decrease vulnerability to depression. Thus, while late-life depression is a recurrent yet highly heterogeneous disorder, better phenotypic characterization provides opportunities to better utilize a range of nonspecific and targeted interventions that can promote recovery, resilience, and maintenance of remission.

Pharmacological and physiological roles of adipokines and myokines in metabolic-related dementia

Dementia is a detrimental neuropathologic condition with considerable physical, mental, social, and financial impact on patients and society. Patients with metabolic syndrome (MetS), a group of diseases that occur in tandem and increase the risk of neurologic diseases, have a higher risk of dementia. The ratio between muscle and adipose tissue is crucial in MetS, as these contain many hormones, including myokines and adipokines, which are involved in crosstalk and local paracrine/autocrine interactions. Evidence suggests that abnormal adipokine and myokine synthesis and release may be implicated in various MetS, such as atherosclerosis, diabetic mellitus (DM), and dyslipidemia, but their precise role is unclear. Here we review the literature on adipokine and myokine involvement in MetS-induced dementia via glucose and insulin homeostasis regulation, neuroinflammation, vascular dysfunction, emotional changes, and cognitive function.

The bidirectional association of 24-h activity rhythms and sleep with depressive symptoms in middle-aged and elderly persons

BACKGROUND

In older populations disturbed 24-h activity rhythms, poor sleep, and depressive symptoms are often lingering and co-morbid, making treatment difficult. To improve insights into these commonly co-occurring problems, we assessed the bidirectional association of sleep and 24-h activity rhythms with depressive symptoms in middle-aged and elderly persons.

METHODS

In 1734 participants (mean age: 62.3 ± 9.3 years, 55% women) from the prospective Rotterdam Study, 24-h activity rhythms and sleep were estimated with actigraphy (mean duration: 146 ± 19.6 h), sleep quality with the Pittsburgh Sleep Quality Index, and depressive symptoms with the Center for Epidemiological Studies Depression scale. Repeated measures were available for 947 participants (54%) over a median follow-up of 6 years (interquartile range = 5.6-6.3). Linear-mixed models were used to assess temporal associations of 24-h activity rhythms and sleep with depressive symptoms in both directions.

RESULTS

High 24-h activity rhythm fragmentation (IV) (B = 1.002, 95% confidence interval (CI) = 0.641-1.363), long time in bed (TIB) (B = 0.111, 95% CI = 0.053-0.169), low sleep efficiency (SE) (B = -0.015, 95% CI = -0.020 to -0.009), long sleep onset latency (SOL) (B = 0.009, 95% CI = 0.006-0.012), and low self-rated sleep quality (B = 0.112, 95% CI = 0.0992-0.124) at baseline were associated with increasing depressive symptoms over time. Conversely, more depressive symptoms at baseline were associated with an increasing 24-h activity rhythm fragmentation (B = 0.002, 95% CI = 0.001-0.003) and TIB (B = 0.009, 95% CI = 0.004-0.015), and a decreasing SE (B = -0.140, 95% CI = -0.196 to -0.084), SOL (B = 0.013, 95% CI = 0.008-0.018), and self-rated sleep quality (B = 0.193, 95% CI = 0.171-0.215) over time.

CONCLUSION

This study demonstrates a bidirectional association of 24-h activity rhythms, actigraphy-estimated sleep, and self-rated sleep quality with depressive symptoms over a time frame of multiple years in middle-aged and elderly persons.

Neuroprotective Roles of Apelin-13 in Neurological Diseases

Apelin is a natural ligand for the G protein-coupled receptor APJ, and the apelin/APJ system is widely distributed in vivo. Among the apelin family, apelin-13 is the major apelin isoform in the central nervous system and cardiovascular system, and is involved in the regulation of various physiopathological mechanisms such as apoptosis, neuroinflammation, angiogenesis, and oxidative stress. Apelin is currently being extensively studied in the nervous system, and apelin-13 has been shown to be associated with the onset and progression of a variety of neurological disorders, including stroke, neurodegenerative diseases, epilepsy, spinal cord injury (SCI), and psychiatric diseases. This study summarizes the pathophysiological roles of apelin-13 in the development and progression of neurological related diseases.

Late-life depression, allostatic load, and risk of dementia: The AGES-Reykjavik study

BACKGROUND

The current study aimed to assess if the relation between depression and dementia could be explained by allostatic load (AL) profiles, as well as assessing their risk on incident all-cause dementia, Alzheimer's disease (AD), and non-AD dementias.

METHODS

The study included individuals without dementia at baseline from the population-based AGES-Reykjavik Study. Depressive symptoms assessed with the Geriatric Depression Scale-15 and AL markers were collected at baseline. Latent profile analysis (LPA) was performed on the AL markers. Incident dementia was measured during 12-years of follow-up. Cox regressions adjusted for AL profiles were performed to evaluate if AL could explain the relation between depressive symptoms and incident dementia. Additional Cox regressions exploring the interaction with depressive symptoms and AL profiles were also performed.

RESULTS

LPA revealed four profiles based on AL factors: 'Low cardiovascular dysregulation' (43 %), 'Average' (42 % prevalence), 'High cardiovascular dysregulation' (11 %), and 'Multisystem dysregulation' (4 %). Cox regression analyses found an increased risk for dementia in the 'Multisystem dysregulation' group (HR 1.72; 95 % CI 1.26-2.33), as well as for AD (HR 1.75; 95 % CI: 1.12-2.71) and non-AD dementias (HR 1.87; 95 % CI: 1.23-2.84). AL profiles did not mediate the risk of all-cause dementia with depressive symptoms; however, there was evidence of additive interaction with depressive symptoms and the 'Multisystem dysregulation' profile and all-cause dementia (RERI 0.15; 95 % CI 0.03-0.26).

CONCLUSION

AL profiles and depressive symptoms were independently related to dementia. Individuals with multisystem dysregulation could be more susceptible to the negative effects of depressive symptomology on incident dementia.

Demographic, clinical and biochemical correlates of the length of stay for different polarities in Chinese inpatients with bipolar disorder: A real-world study

Introduction: Many patients with bipolar disorder (BD) need hospitalization, while the number of hospital beds for these patients is limited. Managing the length of stay (LOS) is an effective solution to this issue. Research on LOS and its influencing factors in BD is limited in China. This study aimed to identify the factors relevant to LOS in different polarities in Chinese patients with BD. Method: This was a real-world, cross-sectional study. Data were obtained from the electronic medical record system. Patients admitted to Beijing Anding Hospital between Jan 2014 and Dec 2017 and diagnosed with BD were included. Demographic information, clinical characteristics, and biochemical variables were collected. Patients were classified into short and long LOS groups based on a cutoff value. A univariate study and a multivariate logistic regression analysis were performed to identify variables related to LOS in various BD polarities. The receiver operating characteristic (ROC) analysis was utilized to evaluate the discrimination accuracy of the regression model. Result: Four thousand six hundred and seventy-five visits from 4,451 individuals were included in the analysis. For the whole sample, unmarried status, psychotic features, and family history of mental disorders were positively associated with long LOS (all p < 0.05). There was an additive interaction between a family history of mental disorders and polarities (p < 0.05). For manic episodes, unmarried status, psychotic features, and family history of mental disorders were positively associated with long LOS (all p < 0.05). For depressive episodes, psychotic features and high-density lipoprotein cholesterol (HDLC) levels were positively associated with long LOS (all p < 0.05). For mixed states, unmarried status was positively associated with long LOS, while low-density lipoprotein cholesterol (LDLC) levels were negatively associated with LOS (all p < 0.05). The area under the curve (AUC) values for depressive episodes, manic episodes, and mixed states in the combined model were 0.587, 0.553, and 0.619, respectively (all p < 0.05). Discussion: The findings suggested that LOS correlates differed by polarity, with marital status, psychotic features, a family history of mental disorders, and lipid levels strongly linked with LOS in patients with BD.

The Role of Inflammation in the Pathophysiology of Depression and Suicidal Behavior: Implications for Treatment

Depression and suicidal behavior are 2 complex psychiatric conditions of significant public health concerns due to their debilitating nature. The need to enhance contemporary treatments and preventative approaches for these illnesses not only calls for distillation of current views on their pathogenesis but also provides an impetus for further elucidation of their novel etiological determinants. In this regard, inflammation has recently been recognized as a potentially important contributor to the development of depression and suicidal behavior. This review highlights key evidence that supports the presence of dysregulated neurometabolic and immunologic signaling and abnormal interaction with microbial species as putative etiological hallmarks of inflammation in depression as well as their contribution to the development of suicidal behavior. Furthermore, therapeutic insights addressing candidate mechanisms of pathological inflammation in these disorders are proposed.

Mental health and periodontal and peri-implant diseases

Mental health disorders, particularly depression and anxiety, affect a significant number of the global population. Several pathophysiological pathways for these disorders have been identified, including the hypothalamic-pituitary-adrenal axis, autonomic nervous system, and the immune system. In addition, life events, environmental factors, and lifestyle affect the onset, progression, and recurrence of mental health disorders. These may all overlap with periodontal and/or peri-implant disease. Mental health disorders are associated with more severe periodontal disease and, in some cases, poorer healing outcomes to nonsurgical periodontal therapy. They can result in behavior modification, such as poor oral hygiene practices, tobacco smoking, and alcohol abuse, which are also risk factors for periodontal disease and, therefore, may have a contributory effect. Stress has immunomodulatory effects regulating immune cell numbers and function, as well as proinflammatory cytokine production. Stress markers such as cortisol and catecholamines may modulate periodontal bacterial growth and the expression of virulence factors. Stress and some mental health disorders are accompanied by a low-grade chronic inflammation that may be involved in their relationship with periodontal disease and vice versa. Although the gut microbiome interacting with the central nervous system (gut-brain axis) is thought to play a significant role in mental illness, less is understood about the role of the oral microbiome. The evidence for mental health disorders on implant outcomes is lacking, but may mainly be through behaviourial changes. Through lack of compliance withoral hygiene and maintenance visits, peri-implant health can be affected. Increased smoking and risk of periodontal disease may also affect implant outcomes. Selective serotonin reuptake inhibitors have been linked with higher implant failure. They have an anabolic effect on bone, reducing turnover, which could account for the increased loss.

Elevated Serum Cortisol Levels in Patients with Focal Epilepsy, Depression, and Comorbid Epilepsy and Depression

Background: The hypothalamic-pituitary-adrenal (HPA) axis, inflammatory processes and neurotrophic factor systems are involved in pathogenesis of both epilepsy and depressive disorders. The study aimed to explore these systems in patients with focal epilepsy (PWE, n = 76), epilepsy and comorbid depression (PWCED n = 48), and major depressive disorder (PWMDD, n = 62) compared with healthy controls (HC, n = 78). Methods: Parameters of the HPA axis, neurotrophic factors, and TNF-α were measured in blood serum along with the hemogram. Results: Serum cortisol level was augmented in PWE, PWCED, and PWMDD compared with HC and was higher in PWMDD than in PWE. Serum cortisol negatively correlated with Mini–Mental State Examination (MMSE) score in PWE, and positively with depression inventory–II (BDI-II) score in PWMDD. Only PWMDD demonstrated elevated plasma ACTH. Serum TNF-α, lymphocytes, and eosinophils were augmented in PWMDD; monocytes elevated in PWE and PWCED, while neutrophils were reduced in PWE and PWMDD. Serum BDNF was decreased in PWE and PWCED, CNTF was elevated in all groups of patients. In PWE, none of above indices depended on epilepsy etiology. Conclusions: The results confirm the involvement of HPA axis and inflammatory processes in pathogenesis of epilepsy and depression and provide new insights in mechanisms of epilepsy and depression comorbidity.

Immune-inflammatory and hypothalamic-pituitary-adrenal axis biomarkers are altered in patients with non-specific low back pain: A systematic review

This systematic review aimed to investigate immune-inflammatory and hypothalamic-pituitary-adrenal (HPA) axis biomarkers in individuals with non-specific low back pain (NSLBP) compared to healthy control. The search was performed in five databases until 4 November 2021. Two reviewers independently conducted screenings, data extraction, risk of bias, and methodological quality assessment of 14 unique studies. All studies reported the source of the fluid analyzed: nine studies used serum, two used plasma, one used serum and plasma, and two studies used salivary cortisol. We found preliminary and limited evidence (only one study for each biomarker) of increased levels in growth differentiation factor 15 (GDF-15), interleukin-23 (IL-23), transforming growth factor–beta (TGF-β), and soluble tumor necrosis factor receptor 1 (sTNF-R1) in NSLBP. Inconsistent and limited evidence was identified for interleukin-10 (IL-10). Although C-reactive protein (CRP), interleukin-6 (IL-6), and tumor necrosis factor–alpha (TNF-α) levels appear to increase in NSLBP, only one study per each biomarker reported statistically significant differences. Interleukin-1 beta (IL-1β), interleukin-17 (IL-17), interferon gamma (IFN-γ), and high-sensitivity CRP (hsCRP) showed no significant differences. Regarding cortisol, one study showed a significant increase and another a significant decrease. More robust evidence between GDF-15, IL-23, TGF-β, and sTNF-R1 with NSLBP is needed. Moreover, contrary to the findings reported in previous studies, when comparing results exclusively with healthy control, insufficient robust evidence for IL-6, TNF-α, and CRP was found in NSLBP. In addition, cortisol response (HPA-related biomarker) showed a dysregulated functioning in NSLBP, with incongruent evidence regarding its directionality. Therefore, our effort is to find adjusted evidence to conclude which immune-inflammatory and HPA axis biomarkers are altered in NSLBP and how much their levels are affected.

Physical Activity Influences Cortisol and Dehydroepiandrosterone (Sulfate) Levels in Older Adults: A Systematic Review and Meta-Analysis

Age-related changes affect the ratio between two steroid hormones of the hypothalamic-pituitary-adrenal axis, cortisol and dehydroepiandrosterone (sulfate) (DHEA[S]). Physical activity (PA) may buffer the effects of chronic stress and counteract the aging decline of DHEA(S). Therefore, a systematic review was conducted to understand how PA influences physiological markers of cortisol and/or DHEA(S) and whether there is a difference in observational associations or experimental effects in older adults aged 65 years and older. A narrative synthesis was performed on nine observational studies, and meta-analyses were performed on 22 randomized controlled trials. There was low- to moderate-quality evidence that regular PA beneficially reduces cortisol and increases DHEA(S) levels. Subgroup analyses showed no clinically important differences between men and women, different exercise modalities, or health states. The findings cautiously suggest that regular PA of older adults' own choice that they find enjoyable could be recommended to improve cortisol and/or DHEA(S) levels.

Anxiety and Depression: What Do We Know of Neuropeptides?

In modern society, there has been a rising trend of depression and anxiety. This trend heavily impacts the population’s mental health and thus contributes significantly to morbidity and, in the worst case, to suicides. Modern medicine, with many antidepressants and anxiolytics at hand, is still unable to achieve remission in many patients. The pathophysiology of depression and anxiety is still only marginally understood, which encouraged researchers to focus on neuropeptides, as they are a vast group of signaling molecules in the nervous system. Neuropeptides are involved in the regulation of many physiological functions. Some act as neuromodulators and are often co-released with neurotransmitters that allow for reciprocal communication between the brain and the body. Most studied in the past were the antidepressant and anxiolytic effects of oxytocin, vasopressin or neuropeptide Y and S, or Substance P. However, in recent years, more and more novel neuropeptides have been added to the list, with implications for the research and development of new targets, diagnostic elements, and even therapies to treat anxiety and depressive disorders. In this review, we take a close look at all currently studied neuropeptides, their related pathways, their roles in stress adaptation, and the etiology of anxiety and depression in humans and animal models. We will focus on the latest research and information regarding these associated neuropeptides and thus picture their potential uses in the future.

Effects of Huolisu Oral Solution on Depression-Like Behavior in Rats: Neurotransmitter and HPA Axis

Background: Depression is a common mental disorder, and its morbidity rate is expected to rank second among all mental disorders by 2020. Hence, traditional Chinese medicines gradually attract the attention of many researchers because of their various targets and low toxicity. Huolisu oral solution (HLS) is a Chinese medicine compound preparation, which is present in the Chinese Pharmacopoeia. It is used clinically mainly for the treatment of neurasthenia, perimenopausal syndrome, and insomnia, or depression associated with cerebrovascular disease. Despite the fact that HLS has been used as an antidepressant in clinics, the underlying mechanism is still an untouched domain. To provide a theoretical basis for the clinical application, a series of assessment methods, such as the tail suspension test (TST), forced swim test (FST), and locomotor activity test in mice and rat models of chronic unpredictable mild stress (CUMS), have been conducted in our study.

Objective: The aim of the study was to explore the antidepressive effect and mechanism of HLS.

Methods: CUMS was induced in rats to simulate a depression-like behavior. Neurotransmitters and hormones were detected by enzyme-link immunosorbent assay (ELISA). Pathomorphology examination of the hippocampus was obtained by using the TSView 7 image analysis system. The active ingredients of HLS were also determined by high-performance liquid chromatography (HPLC).

Results: HLS could alleviate the depression-like behavior of the model rats. Biochemical analysis showed that HLS enhanced the levels of 5-hydroxytryptamine (5-HT), norepinephrine (NE), and dopamine (DA) in the hippocampus and diminished these in the serum of the CUMS rats. HLS could also decrease the concentration of corticosterone (CORT), adrenocorticotropic hormone (ACTH), and β-endorphin (β-EP) in blood. The pathohistological examination revealed that the hippocampus and adrenal gland were improved after treatment with HLS.

Conclusions: This study concluded that HLS could alleviate depression-like behaviors in the rats exposed to CUMS, and the potential mechanism may be related to the regulation of the monoamine neurotransmitters, the hypothalamic–pituitary–adrenal (HPA) axis, and the β-EP. These findings hint that HLS is likely to be a potentially effective agent for treating depression.

Mortality, Morbidity and Health-Related Outcomes in Informal Caregivers Compared to Non-Caregivers: A Systematic Review

A systematic overview of mental and physical disorders of informal caregivers based on population-based studies with good methodological quality is lacking. Therefore, our aim was to systematically summarize mortality, incidence, and prevalence estimates of chronic diseases in informal caregivers compared to non-caregivers. Following PRISMA recommendations, we searched major healthcare databases (CINAHL, MEDLINE and Web of Science) systematically for relevant studies published in the last 10 years (without language restrictions) (PROSPERO registration number: CRD42020200314). We included only observational cross-sectional and cohort studies with low risk of bias (risk scores 0–2 out of max 8) that reported the prevalence, incidence, odds ratio (OR), hazard ratio (HR), mean- or sum-scores for health-related outcomes in informal caregivers and non-caregivers. For a thorough methodological quality assessment, we used a validated checklist. The synthesis of the results was conducted by grouping outcomes. We included 22 studies, which came predominately from the USA and Europe. Informal caregivers had a significantly lower mortality than non-caregivers. Regarding chronic morbidity outcomes, the results from a large longitudinal German health-insurance evaluation showed increased and statistically significant incidences of severe stress, adjustment disorders, depression, diseases of the spine and pain conditions among informal caregivers compared to non-caregivers. In cross-sectional evaluations, informal caregiving seemed to be associated with a higher occurrence of depression and of anxiety (ranging from 4 to 51% and 2 to 38%, respectively), pain, hypertension, diabetes and reduced quality of life. Results from our systematic review suggest that informal caregiving may be associated with several mental and physical disorders. However, these results need to be interpreted with caution, as the cross-sectional studies cannot determine temporal relationships. The lower mortality rates compared to non-caregivers may be due to a healthy-carer bias in longitudinal observational studies; however, these and other potential benefits of informal caregiving deserve further attention by researchers.

Adverse childhood experiences and late-life diurnal HPA axis activity: Associations of different childhood adversity types and interaction with timing in a sample of older East Prussian World War II refugees

Adverse childhood experiences (ACEs) have been associated with unfavorable health outcomes throughout the life up to old age. Mechanisms through which ACEs impact later life health are still not entirely clear. There is growing evidence for the idea that alterations in the hypothalamic pituitary adrenal (HPA) axis might cause the effects of ACEs on later health consequences. Only few studies have investigated associations between ACEs and diurnal HPA axis functioning in older adults. Therefore, we investigated the impact of type and timing of ACEs linked to flight of war on diurnal HPA axis activity in a sample of East Prussian World War II refugees aged 74-91 years. We calculated a dichotomous variable according to the (minimum) age at trauma: early ACE (eACE; 0-5 years) and late ACE (lACE; 6-17 years). Multiple linear regression analysis using different ACEs linked to flight of war (war-related trauma, individual experience of violence, neglect) as well as age at trauma and the interactions of ACEs and age at trauma as predictors and three cortisol outcomes (AUC_G (area under the curve with respect to the ground), decline (morning to night) and CAR (cortisol awakening response)) was performed. For AUC_G, we found a negative association of individual experience of violence only in lACE participants. For decline, a positive association with neglect was observed for the whole study sample. The overall model for CAR was not statistically significant. Our findings support the hypothesis that type as well as timing of ACEs might influence diurnal HPA axis functioning into old age. These findings may contribute to a better understanding of the lifelong influence of ACEs.

The Role of Natural Products in Treatment of Depressive Disorder

Depressive disorder is one of the most common psychiatric syndromes that, if left untreated, can cause many disturbances in a person's life. Numerous factors are involved in depression, including inflammation, brain-derived neurotrophic factor (BDNF), GABAergic system, hypothalamic- pituitary-adrenal (HPA) Axis, monoamine neurotransmitters (serotonin (5-HT), noradrenaline, and dopamine). Common treatments for depression are selective serotonin reuptake inhibitors, tricyclic antidepressants, and monoamine oxidase inhibitors, but these drugs have several side effects such as anxiety, diarrhea, constipation, weight loss, and sexual dysfunctions. These agents only reduce the symptoms and temporarily reduce the rate of cognitive impairment associated with depression. As a result, extensive research has recently been conducted on the potential use of antidepressant and sedative herbs. According to the available data, herbs used in traditional medicine can be significantly effective in reducing depression, depressive symptoms and improving patients' performance. The present study provides a summary of biomarkers and therapeutic goals of depression and shows that natural products such as saffron or genipin have antidepressant effects. Some of the useful natural products and their mechanisms were evaluated. Data on various herbs and natural isolated compounds reported to prevent and reduce depressive symptoms is also discussed.

The co-chaperone FKBP51 modulates HPA axis activity and age-related maladaptation of the stress system in pituitary proopiomelanocortin cells

Glucocorticoid (GC)-mediated negative feedback of the hypothalamic-pituitary-adrenal (HPA) axis, the body's physiological stress response system, is tightly regulated and essential for appropriate termination of this hormonal cascade. Disturbed regulation and maladaptive response of this axis are fundamental components of multiple stress-induced psychiatric and metabolic diseases and aging. The co-chaperone FK506 binding protein 51 (FKBP51) is a negative regulator of the GC receptor (GR), is highly stress responsive, and its polymorphisms have been repeatedly associated with stress-related disorders and dysfunctions in humans and rodents. Proopiomelanocortin (Pomc)-expressing corticotropes in the anterior pituitary gland are one of the key cell populations of this closed-loop GC-dependent negative feedback regulation of the HPA axis in the periphery. However, the cell type-specific role of FKBP51 in anterior pituitary corticotrope POMC cells and its impact on age-related HPA axis disturbances are yet to be elucidated. Here, using a combination of endogenous knockout and viral rescue, we show that male mice lacking FKBP51 in Pomc-expressing cells exhibit enhanced GR-mediated negative feedback and are protected from age-related disruption of their diurnal corticosterone (CORT) rhythm. Our study highlights the complexity of tissue- and cell type-specific, but also cross-tissue effects of FKBP51 in the rodent stress response at different ages and extends our understanding of potential targets for pharmacological intervention in stress- and age-related disorders.

The contribution of social isolation and loneliness to sleep disturbances among older adults: a systematic review

A large number of older people encounter both objective and subjective types of social isolation and sleep disorders. Social isolation increases a person's risk of a wide range of adverse health outcomes and premature death. Social isolation can cause poor sleep quality that has been proposed as one of the possible mechanisms by which social isolation affects people's health and quality of life. The present study was conducted to determine the relationship between objective and subjective social isolation with sleep difficulties among older adults. All articles in PubMed, Web of Science, Scopus, Embase, PsycInfo, and Social care online databases published by December 2020 were systematically searched for relevant published articles. Two authors separately checked the acceptability and quality of the studies using the Newcastle Ottawa checklist. Any disagreement was resolved by consulting the third author. According to the inclusion criteria, 11 studies were systematically reviewed, of which five were cross-sectional, and six were longitudinal studies. No meta-analysis was performed due to the high heterogeneity of the studies. Based on the present study results, both objective and subjective social isolation are related to sleep disturbance in older people. This systematic review showed that objective and subjective social isolation are associated with low sleep quality. It is recommended to investigate the causal relationships and possible pathways that affect the studied variables in future studies.

Chronic Stress and Depression in Periodontitis and Peri-Implantitis: A Narrative Review on Neurobiological, Neurobehavioral and Immune-Microbiome Interplays and Clinical Management Implications

Besides the well-known systemic factors for periodontal and peri-implant diseases, additional co-factors, such as chronic stress and depression, may also affect disease onset and progression as well as treatment responsiveness. Neurobiological and neurobehavioral pathogenic links between chronic stress and depression, on the one side, and periodontitis and peri-implantitis, on the other side, which have been little investigated and principally related to necrotizing periodontal disease, have been reviewed, along with their putative interconnections with periodontal immune-microbiome balance. Rising evidence suggest that dysregulated neurobiological and neurobehavioral factors, as well as periodontal immune-microbiome unbalance, all related to chronic stress and depression, may crucially interact and thus represent contributing factors in the genesis and worsening not only of necrotizing periodontal lesions, but also of chronic periodontitis and peri-implantitis. Such potential interconnections may be even more relevant in recurrent and aggressive cases of periodontal and peri-implant disease, which are frequently refractory to therapy, and may, if corroborated, coherently pave the way for personalized prevention and treatment strategies, possibly targeting immune-microbiome unbalance and neurobehavioral factors and focusing on neurobiological ones, especially in chronically stressed and depressed subjects with periodontitis and peri-implantitis.

Loneliness and isolated living status in middle-aged and older adults in Taiwan: exploration on stress-related biomarkers, depressive symptoms, and disability

PURPOSE

Loneliness is a subjective feeling by which an individual perceives a lack of closeness in interpersonal relationships. An isolated living status is linked with higher odds of risky health behavior. The conflicting impacts of loneliness and isolated living status on stress-related biomarkers, depressive symptoms, and disability remain unexplained.

METHODS

Six hundred twenty-nine participants aged 66.0 (SD=7.3) separated into four groups: "Lonely and Isolated," "Not Lonely, but Isolated," "Lonely, but Not Isolated," and "Neither Lonely, nor Isolated," were retrieved from the Social Environment and Biomarkers of Aging Study conducted in 2000. Follow-up health indicators in 2006 included three stress-related biomarkers, depressive symptoms, and two physical disability indicators. A hierarchical regression was performed for the analysis.

RESULTS

Firstly, compared to the "Neither Lonely nor Isolated" group, only the "Lonely, but Not Isolated" participants at baseline retained positive associations with the stress-related biomarkers levels 6 years later (urine cortisol level (B=9.25, 95% CI=3.24-15.27), serum Interleukin-6 level (B=2.76, 95% CI=0.72-4.79) and the serum high sensitivity C-reactive protein (hsCRP) level (B=0.40, 95% CI=0.17-0.62)). However, such associations were not observed in the "Lonely and Isolated" participants. Secondly, only "Lonely and Isolated" participants at baseline were positively associated with depressive symptoms 6 years later (B=1.70, 95% CI=0.11-3.30). Finally, the associations between combinations of loneliness and isolated living status and physical disability were eliminated after adjusting the covariables.

CONCLUSION

Four combinations of loneliness and isolated living status were associated with different impacts on stress-related biomarkers, depressive symptoms, and physical disability. Further dynamic investigations are warranted.

The interface of COVID-19, diabetes, and depression

Comorbid diabetes with depression is a challenging and often under-recognized clinical problem. During the current COVID-19 pandemic, a communicable disease is thriving on the increasing incidences of these non-communicable diseases. These three different health problems are bidirectionally connected forming a vicious cycle. Firstly, depressed individuals show a higher risk of developing diabetes and patients with diabetes have a higher risk of developing symptoms of depression. Secondly, patients with diabetes have a higher risk of developing severe COVID-19 as well as of experiencing breakthrough infections. Thirdly, in both patients with type 2 diabetes and in COVID-19 survivors the prevalence of depression seems to be increased. Fourthly, lockdown and quarantine measurements during the COVID-19 pandemic has led to an increase in depression. Therefore, it is of importance to increase the awareness of this interface between depression, diabetes and COVID-19. Finally, as symptoms of post-COVID, diabetes and depression may be overlapping, there is a need for educating skilled personnel in the management of these comorbidities.

Microglia and HPA axis in depression: An overview of participation and relationship

Objectives: This narrative review article provides an overview on the involvement of microglia and the hypothalamic-pituitary-adrenal (HPA) axis in the pathophysiology of depression, as well investigates the mutual relationship between these two entities: how microglial activation can contribute to the dysregulation of the HPA axis, and vice versa.Methods: Relevant studies and reviews already published in the Pubmed electronic database involving the themes microglia, HPA axis and depression were used to meet the objectives.Results: Exposition to stressful events is considered a common factor in the mechanisms proposed to explain the depressive disorder. Stress can activate microglial cells, important immune components of the central nervous system (CNS). Moreover, another system involved in the physiological response to stressors is the hypothalamic-pituitary-adrenal (HPA) axis, the main stress response system responsible for the production of the glucocorticoid hormone (GC). Also, mediators released after microglial activation can stimulate the HPA axis, inducing production of GC. Likewise, high levels of GCs are also capable of activating microglia, generating a vicious cycle.Conclusion: Immune and neuroendocrine systems seems to work in a coordinated manner and that their dysregulation may be involved in the pathophysiology of depression since neuroinflammation and hypercortisolism are often observed in this disorder.