Sex Differences in Depression Caused by Early Life Stress and Related Mechanisms

NRXN3-NLGN1 complex influences the development of depression induced by maternal separation in rats

Early-life stress (ELS) increases the risk of major depressive disorder in children and adolescents. However, the molecular and cellular mechanisms of major depressive disorder (MDD) induced by ELS are poorly understood. Here, we establish a stress model in rats in which maternal separation stress (MS) during the postnatal period increases susceptibility to restraint stress (RS) later in life. In terms of mechanism, MS causes long-lasting synaptic plasticity alterations in rats, which is accompanied by reduced branch and spine lengths in the hippocampus. We identified the role of the cell adhesion factor neurexin 3 (NRXN3) and its ligand neuroligin 1 (NLGN1) as mediators of these effects. NRXN3 and NLGN1 downregulation in the hippocampus occurred prior to the observed synaptic changes and depression-related behaviors. In conclusion, NRXN3 is involved in the development of depression induced by maternal separation, and the specific mechanism involves the NRXN3-NLGN1 complex, which can mediate synaptic plasticity and increase susceptibility todepression.

Association between fluoride exposure and psychiatric disorders in adults

To explore the association between fluoride exposure and depression / anxiety in adults, the 1,169 participants were recruited. The demographic information of participants was obtained through questionnaire survey and physical measurements. Morning urine samples were collected, and urinary fluoride (UF) level was determined. Changes in depression and anxiety levels were evaluated using the Patient Health Questionnaire-2 and General Anxiety Disorder-2 scales. The association between psychiatric disorders and UF levels was analyzed. In the total population, the prevalence of depression and anxiety were 3.17% and 4.19%, respectively. These results showed no significant association between depression / anxiety scale scores and UF levels. Logistic regression suggested no significant association between depression / anxiety levels, and UF levels, but there was an interaction between UF and income on depression. Our findings highlighted the interaction between fluoride exposure and monthly income, which may affect depression in adults.

Chronic stress-induced neuroplasticity in the prefrontal cortex: Structural, functional, and molecular mechanisms from development to aging

Chronic stress profoundly affects the structure and function of the prefrontal cortex (PFC), a brain region critical for executive functions and emotional regulation. This review synthesizes current knowledge on stress-induced PFC plasticity, encompassing structural, functional, and molecular changes. We examine how chronic stress leads to dendritic atrophy, spine loss, and alterations in neuronal connectivity within the PFC, particularly affecting the medial PFC. These structural changes are accompanied by disruptions in neurotransmitter systems, most notably glutamatergic and GABAergic signaling, and alterations in synaptic plasticity mechanisms. At the molecular level, we discuss the intricate interplay between stress hormones, neurotrophic factors, and epigenetic modifications that underlie these changes. The review highlights the significant behavioral and cognitive consequences of stress-induced PFC plasticity, including impairments in working memory, decision-making, and emotional regulation, which may contribute to the development of stress-related psychiatric disorders. We also explore individual differences in stress susceptibility, focusing on sex-specific effects and age-dependent variations in stress responses. The role of estrogens in conferring stress resilience in females and the unique vulnerabilities of the developing and aging PFC are discussed. Finally, we consider potential pharmacological and non-pharmacological interventions that may mitigate or reverse stress-induced changes in the PFC. The review concludes by identifying key areas for future research, including the need for more studies on the reversibility of stress effects and the potential of emerging technologies in unraveling the complexities of PFC plasticity. This comprehensive overview underscores the critical importance of understanding stress-induced PFC plasticity for developing more effective strategies to prevent and treat stress-related mental health disorders.

Is the Relationship Between Adolescent Social Isolation and Anxiety-Like Behaviors Altered by Microglia Ablation in Female Long Evans Rats?

OBJECTIVE

Despite extensive, cross-disciplinary research revealing a relationship between early life stress (ELS) and an increased risk for neuropsychiatric disorders, the underlying processes mediating this relationship are not fully understood. Further, the majority of preclinical studies investigating this relationship have not taken sex differences into consideration. A growing body of work suggests that microglia, resident immune cells of the brain, are impacted by ELS and contribute to some of the maladaptive behavioral phenotypes in adulthood. Here, we utilized an adolescent social isolation (aSI) model of ELS in female rats to test the role of microglia in mediating the effects of ELS on anxiety-related behaviors.

METHODS

The present study sought to determine whether microglia ablation during aSI could prevent anxiety-like behaviors in female Long Evans rats. A colony-stimulating factor 1 receptor (CSF1-r) inhibitor, PLX3397, was provided in chow to ablate microglia at the start of the isolation period (postnatal day (P) 21-42). During the aSI period, animals performed a battery of behavioral assays including the open field test, elevated plus maze, and successive alleys test. Following completion of the behavioral assays, brain tissue was collected to confirm the efficacy of PLX3397 and identify changes in microglia population density.

RESULTS

Relative to group-housed (GH) controls, aSI rats showed increased locomotor activity in the open field test and higher closed-arm entries on the elevated plus maze. Although PLX3397 effectively ablated microglia across all animals, this treatment had minimal effects on observed aSI-associated phenotypes.

CONCLUSIONS

Together, these data suggest that microglia are not required for behavioral adaptations promoted by aSI. Future studies will be needed to assess the role of microglia in the relationship between ELS and maladaptive behavioral phenotypes.

The influence of early childhood education and care on the relation between early-life social adversity and children's mental health in the environmental influences for Child Health Outcomes Program

Early adversity increases risk for child mental health difficulties. Stressors in the home environment (e.g., parental mental illness, household socioeconomic challenges) may be particularly impactful. Attending out-of-home childcare may buffer or magnify negative effects of such exposures. Using a longitudinal observational design, we leveraged data from the NIH Environmental influences on Child Health Outcomes Program to test whether number of hours in childcare, defined as 1) any type of nonparental care and 2) center-based care specifically, was associated with child mental health, including via buffering or magnifying associations between early exposure to psychosocial and socioeconomic risks (age 0-3 years) and later internalizing and externalizing symptoms (age 3-5.5 years), in a diverse sample of N = 2,024 parent-child dyads. In linear regression models, childcare participation was not associated with mental health outcomes, nor did we observe an impact of childcare attendance on associations between risk exposures and symptoms. Psychosocial and socioeconomic risks had interactive effects on internalizing and externalizing symptoms. Overall, the findings did not indicate that childcare attendance positively or negatively influenced child mental health and suggested that psychosocial and socioeconomic adversity may need to be considered as separate exposures to understand child mental health risk in early life.

Metformin treatment improves depressive symptoms associated with type 2 diabetes: A 24-week longitudinal study

OBJECTIVE

Metformin is a medication that is widely used for lowering blood sugar in patients with type 2 diabetes. Metformin was shown to have significant antidepressant effects; however, it is not clear whether metformin treatment improves outcomes in patients with type 2 diabetes who have concomitant depressive symptoms.

METHODS

A total of 475 patients with type 2 diabetes mellitus with depressive symptoms were included in this study and divided into metformin and nonmetformin groups according to whether they were taking metformin. The DASS-21 was used to assess patients' depression and anxiety scores before and after a 24-week intervention. In addition, general information about whether the patients had developed complications from diabetes and whether they had been diagnosed with other diseases was assessed.

RESULTS

(1) After 24 weeks, anxiety and depression scores were significantly lower in the metformin group than in the nonmetformin group. (2) The prevalence of depressive symptoms was significantly greater in female type 2 diabetic patients than in male patients (OR = 2.039, 95 % CI = 1.160-3.568). (3) People with type 2 diabetes who develop complications from diabetes (OR = 1.794, 95 % CI = 1.015-3.171) and those diagnosed with other conditions are more likely to experience depressive symptoms.

CONCLUSION

Metformin has an ameliorative effect on type 2 diabetes. However, women, those with diabetes complications, and those with type 2 diabetes who are also diagnosed with other conditions are more likely to experience depressive symptoms.

Early Life Stress and Major Depressive Disorder-An Update on Molecular Mechanisms and Synaptic Impairments

Early life stress (ELS), characterized as abuse, neglect, and abandonment, can cause several adverse consequences in the lives of affected individuals. ELS experiences can affect an individual's development in variable ways, persisting in the long term and promoting lasting impacts, considering that early exposure to stressors can be biologically incorporated, as prolonged stimulation of stress response systems affects the development of the brain structure and other body systems, increasing the risk of diseases associated with stress and cognitive impairment. This type of stress increases the risk of developing major depressive disorder (MDD) in a severe form that does not respond adequately to traditional antidepressant treatments. Several alterations are studied as mechanisms that relate ELS with MDD, such as epigenetic alterations, neurotransmitters, and neuronal signaling. This review discusses research that brings evidence about the ELS mechanisms involved in synaptic impairments and MDD. The processes involved in epigenetic changes and the HPA axis are highlighted, as well as changes in neurotransmitters and neuronal signaling mechanisms.

[Gender characteristics of depressive disorders: clinical, psychological, neurobiological and translational aspects]

Various studies have indicated that the prevalence of depression is almost twice as high among women as among men. A major factor associated with the development of depression and other affective disorders are adverse and psychologically traumatic life events that contribute to changes in the neuroendocrine system, altering the capacity to adapt to stress. These changes are involved in the pathogenesis of mental disorders, along with genetic and other factors, and are to a significant degree regulated by gender dependent mechanisms. While women have a high prevalence of depressive disorders, men show a higher rate of alcohol and substance abuse. These differences in the epidemiology are most likely explained by different predisposition to mental disorders in men and women and a diversity of biological consequences to adverse life events. Taking this into account, there is a need for a critical review of currently used approaches to modeling depressive disorders in preclinical studies, including the use of animals of both sexes. Adaptation of experimental models and protocols taking into account gender characteristics of neuroendocrine changes in response to stress, as well as structural-morphological, electrophysiological, molecular, genetic and epigenetic features, will significantly increase the translational validity of experimental work.

Sex Differences in the Neurobiology of Stress

This review highlights the existing knowledge and data that explain the physiologic impacts of stress, especially pertaining to neurobiology, and how these impacts differ by sex. Furthermore, this review explains the benefits of interventions aimed at preventing or mitigating the adverse effects of stress, because of both the significant toll of stress on the body and the disproportionate impact of these changes experienced by women.

Nutritional Status and Poverty Condition Are Associated with Depression in Preschoolers

Consensus has been reached that symptoms of depression can begin as early as preschool. Nevertheless, only few studies have associated environmental (malnutrition) and social factors (poverty condition, access to health systems, etc.) to the onset of depression in preschoolers. The aim of this study was to explore possible associations between malnutrition (underweight, overweight/obesity), poverty status (home quality, overcrowding), access to healthcare systems and the presence of depressive symptoms in the preschoolers of a semi-rural community. In total, 695 children between 3 and 6 years from the municipality of Chiconcuac, Mexico were evaluated for symptoms of depression with the Preschool Depression Scale for Teachers (ESDM 3-6). Additionally, they were assessed for nutritional status and divided into three groups (low weight, normal weight, overweight/obesity), and their parents were asked to fill out a social demographic questionnaire. Malnutrition status OR = 2.702, 95% CI [1.771-4.145]; UW OR = 4.768, 95% CI [2.570-8.795] and OW/OB OR = 1.959, 95% CI [1.175-3.324]; poverty condition per se OR = 1.779, 95% CI [0.9911-2.630]; housing quality OR = 2.020, 95% CI [0.9606-2.659] and overcrowding = 1.619, 95% CI [0.8989-4.433] were associated to a greater risk for children to show depressive symptoms (DS). Access to healthcare was negatively related with the risk of presenting DS (OR = 0.660, 95% CI [0.3130 to 1.360]). Social and environmental factors such as malnutrition, home quality and overcrowding may increase the risk of presenting DS as soon as in preschool.

High overlap in patients diagnosed with hypermobile Ehlers-Danlos syndrome or hypermobile spectrum disorders with fibromyalgia and 40 self-reported symptoms and comorbidities

Background

Joint pain is a common symptom in patients with hypermobile Ehlers-Danlos Syndrome (hEDS), hypermobility spectrum disorders (HSD) and fibromyalgia. The goal of this study was to determine whether symptoms and comorbidities overlap in patients diagnosed with hEDS/HSD and/or fibromyalgia.

Methods

We retrospectively examined self-reported data from an EDS Clinic intake questionnaire in patients diagnosed with hEDS/HSD, fibromyalgia, or both vs. controls with an emphasis on joint issues.

Results

From 733 patients seen at the EDS Clinic, 56.5% (n = 414) were diagnosed with hEDS/HSD and fibromyalgia (Fibro), 23.8% (n = 167) hEDS/HSD, 13.3% (n = 98) fibromyalgia, or 7.4% (n = 54) none of these diagnoses. More patients were diagnosed with HSD (76.6%) than hEDS (23.4%). Patients were primarily White (95%) and female (90%) with a median age in their 30s (controls 36.7 [18.0, 70.0], fibromyalgia 39.7 [18.0, 75.0], hEDS/HSD 35.0 [18.0, 71.0], hEDS/HSD&Fibro 31.0 [18.0, 63.0]). There was high overlap in all 40 symptoms/comorbidities that we examined in patients diagnosed with fibromyalgia only or hEDS/HSD&Fibro, regardless of whether they had hEDS or HSD. Patients that only had hEDS/HSD without fibromyalgia had far fewer symptoms/comorbidities than patients with hEDS/HSD&Fibro. The top self-reported issues in patients that only had fibromyalgia were joint pain, hand pain when writing or typing, brain fog, joint pain keeping from daily activities, allergy/atopy and headache. Five issues that significantly and uniquely characterized patients diagnosed with hEDS/HSD&Fibro were subluxations (dislocations in hEDS patients), joint issues like sprains, the need to stop sports due to injuries, poor wound healing, and migraine.

Conclusion

The majority of patients seen at the EDS Clinic had a diagnosis of hEDS/HSD plus fibromyalgia that was associated with more severe disease. Our findings indicate that fibromyalgia should be routinely assessed in patients with hEDS/HSD and vis-a-versa to improve patient care.