Voluntary running influences the efficacy of fluoxetine in a model of postpartum depression

Wheel Running During Pregnancy Alleviates Anxiety-and Depression-Like Behaviors During the Postpartum Period in Mice: The Roles of NLRP3 Neuroinflammasome Activation, Prolactin, and the Prolactin Receptor in the Hippocampus

Despite the increase in the prevalence of postpartum depression among maternal disorder, its treatment outcomes remain suboptimal. Studies have shown that exercise can reduce postpartum depressive episodes in the mother, but the effects of exercise during pregnancy on maternal behavior and the potential mechanisms involved remain poorly understood. From the second day of pregnancy to the day of birth, dams exercised for 1 h a day by running on a controlled wheel. The maternal behaviors of the dams were assessed on postpartum day 2 to postpartum day 8. Chronic restraint stress was applied from postpartum day 2 to day 12. Blood was collected on postpartum days 3 and 8, then subjected to ELISA to determine the serum concentration of prolactin. The weight of each dam and the food intake were recorded. Anxiety- and depression-like behavioral tests were conducted, and hippocampal neuroinflammation and prolactin receptor levels were measured. The dams exhibited elevated levels of anxiety and depression, decreased serum prolactin levels, decreased prolactin receptor expression, and activation of NLRP3-mediated neuroinflammation in the hippocampus following the induction of postpartum chronic restraint stress, which were reversed with controlled wheel running during pregnancy. Overall, the findings of this study revealed that the preventive effects of exercise during pregnancy on postpartum anxiety-and depression-like behaviors were accompanied by increased serum prolactin levels, hippocampal prolactin receptor expression and hippocampal NLRP3-mediated neuroinflammation.

PAW, a cost-effective and open-source alternative to commercial rodent running wheels

Voluntary wheel running is a common measure of general activity in many rodent models across neuroscience and physiology. However, current commercial wheel monitoring systems can be cost-prohibitive to many investigators, with many of these systems requiring investments of thousands of dollars. In recent years, several open-source alternatives have been developed, and while these tools are much more cost effective than commercial system, they often lack the flexibility to be applied to a wide variety of projects. Here, we have developed PAW, a 3D Printable Arduino-based Wheel logger. PAW is wireless, fully self-contained, easy to assemble, and all components necessary for its production can be obtained for only $75 CAD. Furthermore, with its compact internal electronics, the 3D printed casing can be easily modified to be used with a wide variety of running wheel designs for a wide variety of rodent species. Data recorded with the PAW system shows circadian patterns of activity which is expected from mice and is consistent with results found in the literature. Altogether, PAW is a flexible, low-cost system that can be beneficial to a broad range of researchers who study rodent models.

The role of stress in perinatal depression and anxiety - A systematic review

Perinatal depression (PND) and anxiety affect around 20% of women, but available pharmacotherapy is not sufficiently effective in 20-60% of them, indicating a need for better understanding of these diseases. Since stress is a significant risk factor for PND, the aim was to examine the role of biological, environmental and psychological stress in PND and anxiety through a systematic literature search. Overall 210 studies were included, among which numerous rodent studies showed that perinatal stress induced depressive-like and anxious behavior, which was associated with HPA-axis alterations and morphological brain changes. Human studies indicated that the relationship between cortisol and perinatal depression/anxiety was not as clear and with many contradictions, although social and psychological stress were clearly positively associated with PND. Finally, oxytocin, synthetic neuroactive steroid and n-3 PUFA diet have been identified as potentially beneficial in the therapy of PND and anxiety, worth to be investigated in the future.

Fecal microbiota as a predictor of acupuncture responses in patients with postpartum depressive disorder

Background

There are several clinical and molecular predictors of responses to antidepressant therapy. However, these markers are either too subjective or complex for clinical use. The gut microbiota could provide an easily accessible set of biomarkers to predict therapeutic efficacy, but its value in predicting therapy responses to acupuncture in patients with depression is unknown. Here we analyzed the predictive value of the gut microbiota in patients with postpartum depressive disorder (PPD) treated with acupuncture.

Methods

Seventy-nine PPD patients were enrolled: 55 were treated with acupuncture and 24 did not received any treatment. The 17-item Hamilton depression rating scale (HAMD-17) was used to assess patients at baseline and after eight weeks. Patients receiving acupuncture treatment were divided into an acupuncture-responsive group or non-responsive group according to HAMD-17 scores changes. Baseline fecal samples were obtained from the patients receiving acupuncture and were analyzed by high-throughput 16S ribosomal RNA sequencing to characterize the gut microbiome.

Results

47.27% patients responded to acupuncture treatment and 12.5% patients with no treatment recovered after 8-week follow-up. There was no significant difference in α-diversity between responders and non-responders. The β-diversity of non-responders was significantly higher than responders. Paraprevotella and Desulfovibrio spp. were significantly enriched in acupuncture responders, and these organisms had an area under the curve of 0.76 and 0.66 for predicting responder patients, respectively.

Conclusions

Paraprevotella and Desulfovibrioare may be useful predictive biomarkers to predict PPD patients likely to respond to acupuncture. Larger studies and validation in independent cohorts are now needed to validate our findings.

Perinatal Depression and the Role of Synaptic Plasticity in Its Pathogenesis and Treatment

Emerging evidence indicates that synaptic plasticity is significantly involved in the pathophysiology and treatment of perinatal depression. Animal models have demonstrated the effects of overstimulated or weakened synapses in various circuits of the brain in causing affective disturbances. GABAergic theory of depression, stress, and the neuroplasticity model of depression indicate the role of synaptic plasticity in the pathogenesis of depression. Multiple factors related to perinatal depression like hormonal shifts, newer antidepressants, mood stabilizers, monoamine systems, biomarkers, neurotrophins, cytokines, psychotherapy and electroconvulsive therapy have demonstrated direct and indirect effects on synaptic plasticity. In this review, we discuss and summarize the various patho-physiology-related effects of synaptic plasticity in depression. We also discuss the association of treatment-related aspects related to psychotropics, electroconvulsive therapy, neuromodulation, psychotherapy, physical exercise and yoga with synaptic plasticity in perinatal depression. Future insights into newer methods of treatment directed towards the modulation of neuroplasticity for perinatal depression will be discussed.

Effect of combination fluoxetine and exercise on prefrontal BDNF, anxiety-like behavior and fear extinction in a female rat model of post-traumatic stress disorder (PTSD): a comparison with male animals

Despite significant differences between men and women in the symptoms of PTSD and the response to therapeutic interventions, most PTSD studies have been done on male subjects. Continuing our previous study in male rats, this study aimed at better understanding the effect of a combination therapy of exercise with fluoxetine on female PTSD rats. The results were then compared with our past findings in male animals. Female adult Wistar rats subjected to PTSD were treated with moderate treadmill exercise or fluoxetine, or a combination of both. PTSD was induced by the single prolonged stress (SPS) model. Elevated plus-maze (EPM), serum and prefrontal BDNF, and fear extinctions were evaluated. The results showed that exercise plus fluoxetine decreased anxiety-like behavior, improved fear extinction, and increased BDNF changes in female rats. The effects of exercise alone were comparable with those of combination therapy except that combination therapy was more effective on OAT (open arm entry). The majority of results in female rats, except for those of prefrontal BDNF, 4th extinction, and OAT, were similar to those of male rats as shown in our previous study. According to our findings, exercise as a safe and cost-effective intervention can be considered as a complementary efficient option for PTSD treatment in both sexes. To achieve better treatment outcomes in PTSD patient, considering sex differences is recommended.

Sex differences in inflammation in the hippocampus and amygdala across the lifespan in rats: associations with cognitive bias

Background

Cognitive symptoms of major depressive disorder, such as negative cognitive bias, are more prevalent in women than in men. Cognitive bias involves pattern separation which requires hippocampal neurogenesis and is modulated by inflammation in the brain. Previously, we found sex differences in the activation of the amygdala and the hippocampus in response to negative cognitive bias in rats that varied with age. Given the association of cognitive bias to neurogenesis and inflammation, we examined associations between cognitive bias, neurogenesis in the hippocampus, and cytokine and chemokine levels in the ventral hippocampus (HPC) and basolateral amygdala (BLA) of male and female rats across the lifespan.

Results

After cognitive bias testing, males had more IFN-γ, IL-1β, IL-4, IL-5, and IL-10 in the ventral HPC than females in adolescence. In young adulthood, females had more IFN-γ, IL-1β, IL-6, and IL-10 in the BLA than males. Middle-aged rats had more IL-13, TNF-α, and CXCL1 in both regions than younger groups. Adolescent male rats had higher hippocampal neurogenesis than adolescent females after cognitive bias testing and young rats that underwent cognitive bias testing had higher levels of hippocampal neurogenesis than controls. Neurogenesis in the dorsal hippocampus was negatively associated with negative cognitive bias in young adult males.

Conclusions

Overall, the association between negative cognitive bias, hippocampal neurogenesis, and inflammation in the brain differs by age and sex. Hippocampal neurogenesis and inflammation may play greater role in the cognitive bias of young males compared to a greater role of BLA inflammation in adult females. These findings lay the groundwork for the discovery of sex-specific novel therapeutics that target region-specific inflammation in the brain and hippocampal neurogenesis.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12979-022-00299-4.

• Adolescent male rats had more hippocampal inflammation than females after cognitive bias testing.

• Adult female rats had more basolateral amygdalar inflammation than males after cognitive bias testing.

• HPC neurogenesis was negatively associated to cognitive bias in young adult male rats.

A functional role of meningeal lymphatics in sex difference of stress susceptibility in mice

Major depressive disorder is one of the most common mental health conditions. Meningeal lymphatics are essential for drainage of molecules in the cerebrospinal fluid to the peripheral immune system. Their potential role in depression-like behaviour has not been investigated. Here, we show in mice, sub-chronic variable stress as a model of depression-like behaviour impairs meningeal lymphatics in females but not in males. Manipulations of meningeal lymphatics regulate the sex difference in the susceptibility to stress-induced depression- and anxiety-like behaviors in mice, as well as alterations of the medial prefrontal cortex and the ventral tegmental area, brain regions critical for emotional regulation. Together, our findings suggest meningeal lymphatic impairment contributes to susceptibility to stress in mice, and that restoration of the meningeal lymphatics might have potential for modulation of depression-like behaviour.

Exercise and yoga during pregnancy and their impact on depression: a systematic literature review

It is well established that exercise can improve depressive symptoms in the general population; however, it is not clear if these benefits are also seen in pregnancy. This review aimed to synthesize the evidence that examines whether exercise during pregnancy impacts depressive and associated symptoms (e.g. anxiety) during the perinatal period. The review was conducted in accordance with PRISMA guidelines and reporting criteria; literature was searched using PubMed, Scopus and Web of Science database engines. Clinical trials published in English evaluating the effects of a defined exercise protocol during pregnancy on depressive and/or anxiety symptoms during the perinatal period were included. Studies without a control group were excluded. Risk of bias was conducted by Cochrane assessment to appraise the quality of the included studies. Twenty-seven articles, between 1994 and 2019, were included. Of these, only 5 specifically recruited women with depression (n = 334), which all assessed a yoga-based intervention; 4 of these studies showed a statistically significant improvement in depressive and/or anxiety symptoms in the intervention group compared to baseline; however, 2 of these studies also showed an improvement in the control group. The remaining 22 studies used various exercise interventions in pregnant women (n = 4808) with 20 studies reporting that exercise during pregnancy has the ability to improve depressive and/or anxiety measures in the perinatal period compared to either baseline or control. The evidence suggests that exercise of various types in pregnancy can reduce depressive and/or anxiety symptoms in the perinatal period in otherwise healthy women. Specifically in women with antenatal depression, the incorporation of yoga in pregnancy can improve depressive/anxiety symptoms in the perinatal period; however, this is based on a small number of studies, and it is not clear whether this is superior to non-exercise controls. Further studies are needed to determine the potential therapeutic effects of exercise of various types during pregnancy on symptoms of antenatal depression.

An overview of the molecular and physiological antidepressant mechanisms of physical exercise in animal models of depression

BACKGROUND

Depression is a global disease that affects the physical and mental health of people of all ages. Non-pharmacological and unconventional methods of treatment, such as regular physical exercise, have been recommended to treat depression.

METHODS

Here, we briefly review the literature about the physiological and molecular mechanisms of exercise antidepressants in depressive-like behavior in animal models of depression.

RESULTS

The main hysiological and molecular mechanisms of physical exercise in depression include blood flow changes in several areas of the brain, increase in brain serotonin synthesis, increase in antioxidant enzymes, increase in serum and brain brain-derived neuro factor (BDNF) levels, decrease in cortisol levels and reduced inflammation in peripheral and brain tissues. Physical exercise also leads to increased activation of the phosphatidylinositol-3-kinase (PI3K), PGC-1α/FNDC5/Irisin pathway, BDNF concentrations (serum and cerebral), extracellular signal-regulated kinase and cAMP-response element binding protein (mainly in neurons of the hippocampus and prefrontal cortex), which together contribute to fight or inhibit the development of depression symptoms. These molecular and physiological mechanisms work in synchrony, further enhancing their effects.

CONCLUSION

Physical exercise can be used as a safe and effective non-pharmacological treatment in depression.

Steroid hormones and hippocampal neurogenesis in the adult mammalian brain

Hippocampal neurogenesis persists across the lifespan in many species, including rodents and humans, and is associated with cognitive performance and the pathogenesis of neurodegenerative disease and psychiatric disorders. Neurogenesis is modulated by steroid hormones that change across development and differ between the sexes in rodents and humans. Here, we discuss the effects of stress and glucocorticoid exposure from gestation to adulthood as well as the effects of androgens and estrogens in adulthood on neurogenesis in the hippocampus. Throughout the review we highlight sex differences in the effects of steroid hormones on neurogenesis and how they may relate to hippocampal function and disease. These data highlight the importance of examining age and sex when evaluating the effects of steroid hormones on hippocampal neurogenesis.

Exercise rather than fluoxetine promotes oligodendrocyte differentiation and myelination in the hippocampus in a male mouse model of depression

Although selective serotonin reuptake inhibitor (SSRI) systems have been meaningfully linked to the clinical phenomena of mood disorders, 15-35% of patients do not respond to multiple SSRI interventions or even experience an exacerbation of their condition. As we previously showed, both running exercise and fluoxetine reversed depression-like behavior. However, whether exercise reverses depression-like behavior more quickly than fluoxetine treatment and whether this rapid effect is achieved via the promotion of oligodendrocyte differentiation and/or myelination in the hippocampus was previously unknown. Sixty male C57BL/6 J mice were used in the present study. We subjected mice with unpredictable chronic stress (UCS) to a 4-week running exercise trial (UCS + RN) or intraperitoneally injected them with fluoxetine (UCS + FLX) to address these uncertainties. At the behavioral level, mice in the UCS + RN group consumed significantly more sugar water in the sucrose preference test (SPT) at the end of the 7th week than those in the UCS group, while those in the UCS + FLX group consumed significantly more sugar water than mice in the UCS group at the end of the 8th week. The unbiased stereological results and immunofluorescence analyses revealed that running exercise, and not fluoxetine treatment, increased the numbers of CC1⁺ and CC1⁺/Olig2⁺/BrdU⁺ oligodendrocytes in the CA1 subfield in depressed mice exposed to UCS. Moreover, running exercise rather than fluoxetine increased the level of myelin basic protein (MBP) and the G-ratio of myelinated nerve fibers in the CA1 subfield in the UCS mouse model. Unlike fluoxetine, exercise promoted hippocampal myelination and oligodendrocyte differentiation and thus has potential as a therapeutic strategy to reduce depression-like behaviors induced by UCS.

Lactation is not required for maintaining maternal care and active coping responses in chronically stressed postpartum rats: Interactions between nursing demand and chronic variable stress

Women who do not breastfeed or discontinue breastfeeding early are more likely to develop postpartum depression (PPD) and stress is a significant risk factor for depression, including PPD. Using a rat model, we investigated whether the absence of nursing would increase the susceptibility to chronic stress-related behavioral and neural changes during the postpartum period. Adult female rats underwent thelectomy (thel; removal of teats), sham surgery, or no surgery (control) and were paired with males for breeding. All litters were rotated twice daily until postpartum day (PD) 26. Sham rats served as surrogates for thel litters, yielding a higher nursing demand for sham rats. Concurrently, rats received either no stress or chronic variable stress until PD 25. Rats were observed for maternal behaviors and tested in a series of tasks including open field, sucrose preference, and forced swim. We used immunohistochemistry (IHC) for doublecortin (DCX; to label immature neurons) or for mineralocorticoid receptor (MR). Contrary to our expectations, non-nursing thel rats were resistant to the effects of stress in all dependent measures. Our data indicate that even in chronic adverse conditions, nursing is not required for maintaining stable care to offspring or active coping responses in an acutely stressful task. We discuss the possible role of offspring contact and consider future directions for biomedical and clinical research. In rats with high nursing demand, however, chronic stress increased immobility, hippocampal neurogenesis, and MR expression (largely in opposition to the effects of stress in rats with typical nursing demand). We discuss these patterns in the context of energetics and allostatic load. This research highlights the complexity in relationships between stress, nursing, and neurobehavioral outcomes in the postpartum period and underscores the need for additional biomedical and clinical research geared toward optimizing treatments and interventions for women with PPD, regardless of breastfeeding status. SIGNIFICANCE STATEMENT: The goal of this research was to determine how the absence of nursing and higher nursing demand impact stress-coping behaviors and neural changes associated with chronic stress in order to disentangle the complex interplay of factors that contribute to psychological illness during the postpartum period.

Ethologically relevant repeated acute social stress induces maternal neglect in the lactating female mouse

Psychosocial stress is a top predictor of peripartum mood disorders in human mothers. In the present study, we developed a novel paradigm testing the effects of direct and vicarious social stress on maternal and mood-related behaviors in B6 mice. Using a novel housing paradigm, we examined the extent to which postpartum dams withdrew from litters following psychosocial stress. Repeated acute direct social stress involved exposing dams to a virgin male mouse for 7 min/day on postpartum days 5-7 during a brief (15-min) mother-pup separation. To remove the effects of direct stress, the vicarious social stress dams were housed in the same vivarium as direct social stressed dams, but without direct exposure to intruders. Control dams were given mock intruder exposure and housed in a separate vivarium room containing breeding mice. All dams experienced pup separation, and maternal care was investigated upon reunion. Direct and vicarious social stress induced significant deficits in maternal care and increased maternal anxiety relative to controls. Although vicarious stress effects were more likely to occur on days when there was acute stress exposure, direct stress sustained maternal deficits 24 h after the final stressor. Together, these data suggest psychosocial stress induces aberrant maternal phenotypes in mice.

Maternal fluoxetine reduces hippocampal inflammation and neurogenesis in adult offspring with sex-specific effects of periadolescent oxytocin

Untreated perinatal depression can have severe consequences for the mother and her children. However, both the efficacy to mothers and safety to exposed infants of pharmacological antidepressants such as selective serotonin reuptake inhibitors (SSRIs), have been questioned. We previously reported that maternal SSRI exposure increased hippocampal IL-1β levels, which may be tied to limited efficacy of SSRIs during the postpartum to the dam but is not yet known whether maternal postpartum SSRIs affect the neuroinflammatory profile of adult offspring. In addition, although controversial, perinatal SSRI exposure has been linked to increased risk of autism spectrum disorder (ASD) in children. Oxytocin (OT) is under investigation as a treatment for ASD, but OT is a large neuropeptide that has difficulty crossing the blood-brain barrier (BBB). Triozan^TM is a nanoformulation that can facilitate OT to cross the BBB. Thus, we investigated the impact of maternal postpartum SSRIs and offspring preadolescent OT treatment on adult offspring neuroinflammation, social behavior, and neurogenesis in the hippocampus. Using a model of de novo postpartum depression, corticosterone (CORT) was given in the postpartum to the dam with or without treatment with the SSRI, fluoxetine (FLX) for 21 days postpartum. Offspring were then subsequently treated with either OT, OT + Triozan^TM, or vehicle for 10 days prior to adolescence (PD25-34). Maternal FLX decreased hippocampal IL-10 and IL-13 and neurogenesis in both sexes, whereas maternal CORT increased hippocampal IL-13 in both sexes. Maternal CORT treatment shifted the neuroimmune profile towards a more proinflammatory profile in offspring hippocampus, whereas oxytocin, independent of formulation, normalized this profile. OT treatment increased hippocampal neurogenesis in adult males but not in adult females, regardless of maternal treatment. OT treatment increased the time spent with a novel social stimulus animal (social investigation) in both adult male and female offspring, although this effect depended on maternal CORT. These findings underscore that preadolescent exposure to OT can reverse some of the long-lasting effects of postpartum maternal CORT and FLX treatments in the adult offspring. In addition, we found that maternal treatments that reduce (CORT) or increase (FLX) hippocampal inflammation in dams resulted in opposing patterns of hippocampal inflammation in adult offspring.

Adult Neural Stem Cells as Promising Targets in Psychiatric Disorders

The development of new therapies for psychiatric disorders is of utmost importance, given the enormous toll these disorders pose to society nowadays. This should be based on the identification of neural substrates and mechanisms that underlie disease etiopathophysiology. Adult neural stem cells (NSCs) have been emerging as a promising platform to counteract brain damage. In this perspective article, we put forth a detailed view of how NSCs operate in the adult brain and influence brain homeostasis, having profound implications at both behavioral and functional levels. We appraise evidence suggesting that adult NSCs play important roles in regulating several forms of brain plasticity, particularly emotional and cognitive flexibility, and that NSC dynamics are altered upon brain pathology. Furthermore, we discuss the potential therapeutic value of utilizing adult endogenous NSCs as vessels for regeneration, highlighting their importance as targets for the treatment of multiple mental illnesses, such as affective disorders, schizophrenia, and addiction. Finally, we speculate on strategies to surpass current challenges in neuropsychiatric disease modeling and brain repair.

Postpartum corticosterone and fluoxetine shift the tryptophan-kynurenine pathway in dams

Perinatal depression (PND) affects 15% of mothers. Selective serotonin reuptake inhibitors (SSRIs) are currently the first-line of treatment for PND but are not always efficacious. Previously, we found significant reductions in plasma tryptophan concentrations and higher hippocampal proinflammatory cytokine, IL-1β levels, due to maternal SSRI treatment. Both inflammation and tryptophan-kynurenine metabolic pathway (TKP) are associated with SSRI efficacy in individuals with major depressive disorder (MDD). TKP is divided into neuroprotective and neurotoxic pathways. Higher metabolite concentrations of the neurotoxic pathway are associated with depression onset and implicated in SSRI efficacy. Metabolites in TKP were investigated in a rodent model of de novo postpartum depression (PPD) given treatment with the SSRI, fluoxetine (FLX). Dams were administered corticosterone (CORT) (40 mg/kg, s.c.), and treated with the SSRI, fluoxetine (FLX) (10 mg/kg, s.c.), during the postpartum for 22 days after parturition. Plasma TKP metabolite concentrations were quantified on the last day of treatment. Maternal postpartum CORT increased neurotoxic metabolites and co-enzyme/cofactors in dams (3-hydroxykynurenine, 3-hydroxyanthranilic acid, vitamin B2, flavin adenine dinucleotide). The combination of both CORT and FLX shifted the neuroprotective-to-neurotoxic ratio towards neurotoxicity. Postpartum FLX decreased plasma xanthurenic acid concentrations. Together, our data indicate higher neurotoxic TKP expression due to maternal postpartum CORT treatment, similar to clinical presentation of MDD. Moreover, maternal FLX treatment showed limited efficacy to influence TKP metabolites, which may correspond to its limited efficacy to treat depressive-like endophenotypes in the postpartum. Overall suggesting changes in TKP may be used as a biomarker of de novo PPD and antidepressant efficacy and targeting this pathway may serve as a potential therapeutic target.

Hippocampal miRNA-144 Modulates Depressive-Like Behaviors in Rats by Targeting PTP1B

BACKGROUND

Depression is the common mental disorder in the world. However, the pathophysiology mechanism underlying depression remains elusive. It has been reported that aberrant expression of miR-144 is closely related to depression. This study was to investigate whether and how miR-144 involves in depressive-like behaviors in a chronic unpredictable mild stress (CUMS) animal model.

METHODS

A rat model of CUMS was established, and qRT-PCR was performed to detect the expression of miR-144 in the hippocampus of a depressed rat. The lentiviral vector carried miR-144 (LV-miR-144) was injected into the hippocampus of the CUMS rat to investigate the effects of miR-144 on the behaviors and PTP1B/TrkB/BDNF signal transduction in the hippocampus of the rat. The interaction between miR-144 and PTP1B was investigated by biological analyses and dual-luciferase reporter assay.

RESULTS

The results showed that CUMS rats had typical depressive behaviors, and the expression of miR-144 in the hippocampus of CUMS rats was significantly lower than that of the control group. In addition, PTP1B protein expression was significantly up-regulated, while the expression of pTrkB and BDNF protein was significantly down-regulated in the hippocampus of CUMS rats. Moreover, PTP1B was a direct target of miR-144, and miR-144 could activate the downstream TrkB/BDNF signaling pathway by inhibiting the expression of PTP1B in primary hippocampus neurons.

CONCLUSION

MiR-144 played an anti-depressive role in hippocampus dysfunction by inhibiting PTP1B and activating the TrkB/BDNF signaling pathway in the hippocampus of CUMS rats.

Effects of Physical Exercise on Neuroplasticity and Brain Function: A Systematic Review in Human and Animal Studies

Background

Physical exercise (PE) has been associated with increase neuroplasticity, neurotrophic factors, and improvements in brain function.

Objective

To evaluate the effects of different PE protocols on neuroplasticity components and brain function in a human and animal model.

Methods

We conducted a systematic review process from November 2019 to January 2020 of the following databases: PubMed, ScienceDirect, SciELO, LILACS, and Scopus. A keyword combination referring to PE and neuroplasticity was included as part of a more thorough search process. From an initial number of 20,782 original articles, after reading the titles and abstracts, twenty-one original articles were included. Two investigators evaluated the abstract, the data of the study, the design, the sample size, the participant characteristics, and the PE protocol.

Results

PE increases neuroplasticity via neurotrophic factors (BDNF, GDNF, and NGF) and receptor (TrkB and P75NTR) production providing improvements in neuroplasticity, and cognitive function (learning and memory) in human and animal models.

Conclusion

PE was effective for increasing the production of neurotrophic factors, cell growth, and proliferation, as well as for improving brain functionality.

Perinatal depression: Heterogeneity of disease and in animal models

Perinatal depression (PND) can have either an antepartum or postpartum onset. Although the greatest risk factor for PND is previous depression history,de novoPND occurs with the majority of cases occurring in the postpartum. Timing of depression can impact etiology, prognosis, and response to treatment. Thus, it is crucial to study the impact of the heterogeneity of PND for better health outcomes. In this review, we outline the differences between antepartum and postpartum depression onset of PND. We discuss maternal physiological changes that differ between pregnancy and postpartum and how these may differentially impact depression susceptibility. We highlight changes in the maternal steroid and peptide hormone levels, immune signalling, serotonergic tone, metabolic factors, brain morphology, and the gut microbiome. Finally, we argue that studying the heterogeneity of PND in clinical and preclinical models can lead to improved knowledge of disease etiopathology and treatment outcomes.

Efficacy of transcranial magnetic stimulation and fluoxetine in the treatment of postpartum depression: A protocol for systematic review and meta-analysis

BACKGROUND

Numerous studies have reported that transcranial magnetic stimulation (TMS) and fluoxetine is used in the treatment of postpartum depression (PPD). Currently, no study has systematically investigated the efficacy and safety of TMS and fluoxetine for the treatment of patients with PPD. Thus, this study will assess the efficacy and safety of TMS and fluoxetine for treating PPD.

METHODS

Relevant studies involving TMS and fluoxetine for the treatment of patients with PPD will be comprehensively searched from the electronic databases from inception to the February 1, 2020: Cochrane Library, EMBASE, MEDILINE, CINAHL, AMED, WANGFANG, VIP, and CNKI databases. No language and publication time restrictions will be applied. RevMan 5.3 software will be utilized for data pooling, data analysis, and risk of bias evaluation. If necessary, we will also assess reporting bias using funnel plot and Egger test.

RESULTS

This study will comprehensively summarize the existing evidence to assess the efficacy and safety of TMS and fluoxetine for treating PPD.

CONCLUSION

The findings of this study may help to establish a better approach to treat PPD using TMS and fluoxetine.

DISSEMINATION AND ETHICS

This study will be disseminated through a peer-reviewed journal. This study does not need ethical approval as no primary patient data will be used.

SYSTEMATIC REVIEW REGISTRATION

INPLASY202040017.

Effect of sertraline on central serotonin and hippocampal plasticity in pregnant and non-pregnant rats

One of the most frequently prescribed selective serotonin reuptake inhibitor medications (SSRIs) for peripartum mood and anxiety disorders is sertraline (Zoloft®). Sertraline can help alleviate mood and anxiety symptoms in many women but it is not known how sertraline, or SSRIs in general, affect the neurobiology of the brain particularly when pregnant. The aim of this study was to investigate how sertraline affects plasticity in the hippocampus, a brain area integral in depression and SSRI efficacy (particularly in males), during late pregnancy and whether these effects differ from the effects of sertraline in non-pregnant females. To do this pregnant and age-matched non-pregnant female Sprague-Dawley rats were used. For the last half of pregnancy (10 days), and at matched points in non-pregnant females, rats were given sertraline (2.5 mg/kg/day or 10 mg/kg/day) or vehicle (0 mg/kg/day). Brains were used to investigate effects on the serotonergic system in the hippocampus and prefrontal cortex and measures of neuroplasticity in the hippocampus. Results show that pregnant females have significantly higher serum levels of sertraline compared to non-pregnant females but that rates of serotonin turnover in the hippocampus and PFC are similar between pregnant and non-pregnant females. Sertraline increased synaptophysin density in the dentate gyrus and CA3 and was associated with a decrease in cell proliferation in the dentate gyrus of non-pregnant, but not pregnant, females. During late pregnancy the hippocampus showed significant reductions in neurogenesis and increases in synaptophysin density. This research highlights the need to consider the unique effect of reproductive state on the neuropharmacology of SSRIs.

Mir363-3p attenuates post-stroke depressive-like behaviors in middle-aged female rats

Women are more likely to develop Post Stroke Depression (PSD) than men and generally do not respond well to anti-depressants with age. This study investigated the effect of microRNA mir363-3p treatment on PSD using a physiologically-relevant animal model. Our previous work showed that mir363-3p treatment, delivered post-stroke, effectively reduces infarct volume in the acute phase of stroke in middle-aged females but not males. Middle-aged female Sprague Dawley rats were tested for baseline sensory motor function and depressive-like behaviors, and then subjected to ischemic stroke via middle cerebral artery occlusion (MCAo) or sham surgery. Animals received either control oligos (MCAo+scrambled, Sham+scrambled) or mir363-3p (MCAo+mir363-3p, Sham+mir363-3p) treatment 4 h later. Sensory motor function and depressive-like behaviors were reassessed up to 100 d after stroke, and circulating levels of IL-6, TNF-alpha and Brain-Derived Neurotrophic Factor (BDNF) were quantified at regular intervals. Prior to termination, Fluorogold was injected into the striatum to assess meso-striatal projections. MCAo+scrambled animals had impaired sensorimotor performance in the acute phase (5 days) of stroke and developed anhedonia, decreased sociability and increased helplessness in the chronic phase. MCAo+mir363-3p animals showed significantly less sensory motor impairment and fewer depressive-like behaviors. IL-6 and TNF-alpha were elevated transiently at 4 weeks after MCAo in both groups. BDNF levels decreased progressively after stroke in the MCAo+scrambled group, and this was attenuated in the mir363-3p group. The number of retrogradely-labeled SNc and VTA cells was reduced in the ischemic hemisphere of the MCAo+scrambled group. In contrast, there was no interhemispheric difference in the number of retrogradely-labeled SNc and VTA cells of MCAo+mir363-3p treated animals. Our results support a therapeutic role for mir363-3p for long-term stroke disability.

The long and short term effects of motherhood on the brain

Becoming a mother is associated with dramatic changes in physiology, endocrinology, immune function, and behaviour that begins during pregnancy and persists into the postpartum. Evidence also suggests that motherhood is accompanied by long-term changes in brain function. In this review, we summarize the short (pregnancy and postpartum) and long-term (beyond the postpartum and into middle age) effects of pregnancy and motherhood on cognition, neuroplasticity, and neuroimmune signalling. We also discuss the effects of previous history of pregnancy and motherhood (parity) on brain health and disease (neurodegenerative diseases and stroke outcomes) and on efficacy of hormone and antidepressant treatments. Finally, we argue that pregnancy and motherhood are unique female experiences that need to be taken into account to better understand female brain function and aging.

Serotonin and motherhood: From molecules to mood

Emerging research points to a valuable role of the monoamine neurotransmitter, serotonin, in the display of maternal behaviors and reproduction-associated plasticity in the maternal brain. Serotonin is also implicated in the pathophysiology of numerous affective disorders and likely plays an important role in the pathophysiology of maternal mental illness. Therefore, the main goals of this review are to detail: (1) how the serotonin system of the female brain changes across pregnancy and postpartum; (2) the role of the central serotonergic system in maternal caregiving and maternal aggression; and (3) how the serotonin system and selective serotonin reuptake inhibitor medications (SSRIs) are involved in the treatment of maternal mental illness. Although there is much work to be done, studying the central serotonin system's multifaceted role in the maternal brain is vital to our understanding of the processes governing matrescence and the maintenance of motherhood.

Sex differences in depression: Insights from clinical and preclinical studies

Depression represents a global mental health concern, and disproportionally affects women as they are twice more likely to be diagnosed than men. In this review, we provide a summary of evidence to support the notion that differences in depression between men and women span multiple facets of the disease, including epidemiology, symptomology, treatment, and pathophysiology. Through a lens of biological sex, we overview depression-related transcriptional patterns, changes in neuroanatomy and neuroplasticity, and immune signatures. We acknowledge the unique physiological and behavioral demands of pregnancy and motherhood by devoting special attention to depression occurring in the peripartum period. Specifically, we discuss issues surrounding the presentation, time course, treatment, and neurobiology of peripartum depression. We write this review with the intention of highlighting the encouraging advancements in our understanding of sex differences in depression, while underscoring the gaps that remain. A more systematic consideration of biological sex as a variable in depression research will be critical in the discovery and development of pharmacotherapies that are efficacious for both men and women.

Depression and adult neurogenesis: Positive effects of the antidepressant fluoxetine and of physical exercise

Of wide interest for health is the relation existing between depression, a very common psychological illness, accompanied by anxiety and reduced ability to concentrate, and adult neurogenesis. We will focus on two neurogenic stimuli, fluoxetine and physical exercise, both endowed with the ability to activate adult neurogenesis in the dentate gyrus of the hippocampus, known to be required for learning and memory, and both able to counteract depression. Fluoxetine belongs to the class of selective serotonin reuptake inhibitor (SSRI) antidepressants, which represent the most used pharmacological therapy; physical exercise has also been shown to effectively counteract depression symptoms in rodents as well as in humans. While there is evidence that the antidepressant effect of fluoxetine requires its pro-neurogenic action, exerted by promoting proliferation, differentiation and survival of progenitor cells of the hippocampus, on the other hand fluoxetine exerts also neurogenesis-independent antidepressant effects by influencing the plasticity of the new neurons generated. Similarly, the antidepressant action of running also correlates with an increase of hippocampal neurogenesis and plasticity, although the gene pathways involved are only partially coincident with those of fluoxetine, such as those involved in serotonin metabolism and synapse formation. We further discuss how extra-neurogenic actions are also suggested by the fact that, unlike running, fluoxetine is unable to stimulate neurogenesis during aging, but still displays antidepressant effects. Moreover, in specific conditions, fluoxetine or running activate not only progenitor but also stem cells, which normally are not stimulated; this fact reveals how stem cells have a long-term, hidden ability to self-renew and, more generally, that neurogenesis is subject to complex controls that may play a role in depression, such as the type of neurogenic stimulus or the state of the local niche. Finally, we discuss how fluoxetine or running are effective in counteracting depression originated from stress or neurodegenerative diseases.

Maternal exercise increases but concurrent maternal fluoxetine prevents the increase in hippocampal neurogenesis of adult offspring

Treating postpartum depression (PPD) with pharmacological antidepressants like fluoxetine (FLX) is complicated because these drugs can remain active in breast milk and potentially affect infant development. Alternatively, non-pharmacological treatments such as exercise are associated with beneficial effects on infant development but its potential ability to counter the effects of PPD are largely unknown. To investigate this, we treated dams with corticosterone (CORT) or vehicle (sesame oil) from postpartum days 2-25 to model PPD. Within oil and CORT treatments, dams were also assigned to one of these treatments: 1) exercise (voluntary running wheel) + FLX (10 mg/kg, i.p.), 2) exercise + saline (vehicle for FLX), 3) no exercise + FLX, 4) no exercise + saline. Both male and female offspring were analyzed, and this generated a total of 16 experimental groups for this study. Adult male and female offspring (125 d old) of these dams were tested for anxiety-like behavior in the novelty suppressed feeding test and stress reactivity in the dexamethasone suppression test. Hippocampal tissue was processed for doublecortin, a protein expressed in immature neurons. Regardless of sex, maternal exercise increased neurogenesis in the dorsal hippocampus of adult offspring, but concurrent exposure to maternal fluoxetine prevented this effect. Exposure to either maternal exercise or maternal FLX facilitated HPA negative feedback in adult males but not females. Maternal postpartum CORT also facilitated HPA feedback in adult offspring of both sexes. Collectively, these data indicate that maternal exercise increased dorsal hippocampal neurogenesis in both sexes but differentially affected offspring HPA axis based on sex. Alternatively, maternal postpartum FLX facilitated HPA axis negative feedback only in males. These findings indicate that different types of maternal interventions bear long-term effects on offspring outcome with implications for treating PPD.

Paroxetine blunts the corticosterone response to swim-induced stress and increases depressive-like behavior in a rat model of postpartum depression

Perinatal depression (PND) affects 15% of women. During the perinatal period both stress- and gonadal hormones fluctuate widely. Putatively, these fluctuations are involved in PND disease mechanisms. The serotonin system is sensitive to such hormone fluctuations, and serotonin reuptake inhibitors (SSRIs) are used to treat PND, although treatment is suboptimal and it is not known at which peripartum time-point SSRI treatment may be most efficacious. In this study, we investigate the effect of the SSRI paroxetine (5mg/kgs.c.) on swim stress-induced corticosterone in a rat model of postpartum depression. In the rat model corticosterone (CORT; 40mg/kgs.c.) was administered in Sprague Dawley rats across postpartum day (PD)2 to PD14. Stress response was measured during the first exposure to the forced swim test (FST1), and depressive-like behavior was measured in both FST1 and FST2. We found that paroxetine completely blunted the swim stress-induced CORT response and increased depressive-like behavior in both FST1 and FST2. Our findings suggest that in the postpartum context, SSRIs compromise stress axis dynamics, which are needed for a healthy stress response. This is likely unfavorable for reversing depressive-like behavior and may provide a rationale for augmentation strategies beyond SSRIs alone to optimize the clinical management of PND.

Hormonal Regulation of Hippocampal Neurogenesis: Implications for Depression and Exercise

Adult hippocampal neurogenesis exists in all mammalian species, including humans, and although there has been considerable research investigating the function and regulation of neurogenesis, there remain many open questions surrounding the complexity of this phenomenon. This stems partially from the fact that neurogenesis is a multistage process that involves proliferation, differentiation, migration, survival, and eventual integration of new cells into the existing hippocampal circuitry, each of which can be independently influenced. The function of adult neurogenesis in the hippocampus is related to stress regulation, behavioral efficacy of antidepressants, long-term spatial memory, forgetting, and pattern separation. Steroid hormones influence the regulation of hippocampal neurogenesis, stress regulation, and cognition and differently in males and females. In this chapter, we will briefly tap into the complex network of steroid hormone modulation of neurogenesis in the hippocampus with specific emphasis on stress, testosterone, and estrogen. We examine the possible role of neurogenesis in the etiology of depression and influencing treatment by examining the influence of both pharmacological (selective serotonin reuptake inhibitors, tricyclic antidepressants) treatments and non-pharmacological (exercise) remedies.