Potential application of helminth therapy for resolution of neuroinflammation in neuropsychiatric disorders

Neuropsychiatric disorders (NPDs) are among the major debilitating disorders worldwide with multiple etiological factors. However, in recent years, psychoneuroimmunology uncovered the role of inflammatory condition and autoimmune disorders in the etiopathogenesis of different NPDs. Hence, resolution of inflammation is a new therapeutic target of NPDs. On the other hand, Helminth infections are among the most prevalent infectious diseases in underdeveloped countries, which usually caused chronic infections with minor clinical symptoms. Remarkably, helminths are among the master regulator of inflammatory reactions and epidemiological studies have shown an inverse association between prevalence of autoimmune disorders with these infections. As such, changes of intestinal microbiota are known to be associated with inflammatory conditions in various NPDs. Conversely, helminth colonization alters the intestinal microbiota composition that leads to suppression of intestinal inflammation. In animal models and human studies, helminths or their antigens have shown to be protected against severe autoimmune and allergic disorders, decline the intensity of inflammatory reactions and improved clinical symptoms of the patients. Therefore, "helminthic therapy" have been used for modulation of immune disturbances in different autoimmunity illnesses, such as Multiple Sclerosis (MS) and Inflammatory Bowel Disease (IBD). Here, it is proposed that "helminthic therapy" is able to ameliorate neuroinflammation of NPDs through immunomodulation of inflammatory reactions and alteration of microbiota composition. This review discusses the potential application of "helminthic therapy" for resolution of neuroinflammation in NPDs.

Marriage and Gut (Microbiome) Feelings: Tracing Novel Dyadic Pathways to Accelerated Aging

Within a couple, partners influence each other's mental and physical health. This review focuses on how couples' relationships, the partners' individual and joint vulnerabilities, and their health behaviors influence health through changes in the gut microbiota, metabolism, and immune function. Couples' shared stressors and emotions and their intertwined lifestyles and routines serve to promote common disease risks in part through parallel changes in their gut microbiotas. Marital discord, stress, and depression have strong bidirectional links, fueling one another. Chronic marital stress and depression can elevate the risk for obesity, metabolic syndrome, and cardiovascular disease by altering resting energy expenditure, insulin production, and triglyceride responses after unhealthy meals. During stressful times, health behaviors typically suffer-and sleep disturbances, poor diets, and sedentary behavior all influence these metabolic pathways while also promoting gut dysbiosis. Dysbiosis increases intestinal permeability (gut leakiness), providing a mechanistic pathway from marital distress and depression to heightened inflammation and accelerated aging. Age-related changes in the gut microbiota's composition and gut leakiness foster immunosenescence, as well as the progression of inflamm-aging; these age-related risks may be altered by stress and depression, diet, sleep, exercise habits, and developmental shifts in emotion regulation strategies. Consideration of the strong mutual influences that partners have on each other's mood and health behaviors, as well as the biological pathways that underlie these influences, provides a new way to view marriage's health implications.

Two Distinct Immune Pathways Linking Social Relationships With Health: Inflammatory and Antiviral Processes

OBJECTIVE

Social relationships can both influence and be influenced by immune processes. Past work implicates two distinct pathways along which this interaction may occur: inflammatory processes and antiviral processes. This article reviews how social behavior is modulated by these two immune processes and how such processes may in turn regulate social behavior.

METHODS

This narrative review outlines existing work on social behavior and both inflammatory and antiviral processes. We propose an evolutionary framework that aims to integrate these findings. Specifically, social isolation has evolutionarily increased the likelihood of wounding and therefore increased the need for inflammation, which works to promote healing. Conversely, broader social networks provide protection from physical threats but also lead to increased pathogen exposure, necessitating a more robust antiviral response.

RESULTS

This review highlights that social adversity, such as social exclusion or loneliness, is associated with increased inflammation, whereas social contact is associated with increased antiviral immunity. Furthermore, increased inflammation leads to sensitivity to social stimuli, presumably to avoid hostile conspecifics and approach allies who may provide care while vulnerable. Individuals with inadequate antiviral immunity engage in behaviors that minimize pathogen exposure, such as reduced affiliative behavior.

CONCLUSIONS

This review suggests that adverse social experiences (social isolation, perceived social threat) may induce inflammatory responses while suppressing antiviral immunity, whereas positive experiences of social connection may reduce inflammation and bolster antiviral responses. Although acutely elevated inflammation would be adaptive under conditions where wounding is likely, chronic inflammation related to continued social adversity may have detrimental health consequences.

Apelin attenuates depressive-like behavior and neuroinflammation in rats co-treated with chronic stress and lipopolysaccharide

Several experimental studies have proved that activation of neuroinflammation pathways may contribute to the development of depression, a neuropsychiatric disorder disease. Our previous studies have shown the antidepressant properties of apelin, but the mechanism was unkown. This study was performed to verify whether the antidepressant effect of apelin was related to its anti-inflammation effect in the central nervous system. To achieve our aim, we selected the co-treatment of chronic stress and LPS to induced an inflammatory process in rats. The effect of this co-treatment was evaluated through the expression of inflammatory markers and glial cell activation. LPS injection co-treated with unpredictable chronic mild stress resulted in the activation of microglial cell and astrocyte, expression of inflammatory markers and depressive behaviors. Treatment with apelin significantly attenuates the deleterious effects in these rats. Our results showed that apelin improved depressive phenotype and decreased the activation of glial cells in stress co-treatment group. The down-regulations of p-NF-κB and p-IKKβ suggested that the effects are possibly mediated by inhibition of the NF-κB-mediated inflammatory response. These findings speculated that intracerebroventricular injection of apelin could be a therapeutic approach for the treatment of depression, and the antidepressant function of apelin may closely associated with its alleviation in neuroinflammation.

Role of gut microbiota in the interaction between immunity and psychiatry: a literature review

BACKGROUND

Psychiatric disorders may be correlated with a low-grade systemic inflammation but the origin of this inflammatory response remains unclear and both genetics and environmental factors seems to be concerned. Recent researches observed that gut microbiota seems to have an impact on the brain and immune processes.

METHOD

We review recent literature to a better understanding of how microbiota interacts with brain, immunity and psychiatric disorders. We search on Pubmed, PsycINFO, PsycARTICLES and Sciencedirect articles with the keywords "gastrointestinal microbiota" and "mental disorders" or "psychological stress".

RESULTS

We showed links between gut microbiota and brain-gut axis regulation, immune and endocrine system activity, neurophysiological changes, behavior variations and neuropsychiatric disorders. Communications between brain and gut are bidirectional via neural, endocrine and immune pathway. Microbiota dysbiosis and increase gut permeability with subsequent immune challenges seems to be the source of the chronic mild inflammation associated with neuropsychiatric disorders. Repeated immune or stress events early in life may lead to neurodevelopmental disorders or sickness behavior later in life.

CONCLUSIONS

Psychological stress impact gut microbiota with subsequent immune activation leading to neurodevelopmental disorders or sickness behavior and altering neurophysiology and reactivity to stress or lifestyle.

Inflammation in Tic Disorders and Obsessive-Compulsive Disorder: Are PANS and PANDAS a Path Forward?

This review and commentary is the product of an invited lecture called "Autoimmunity: PANS/PANDAS" presented at the 2018 Neurobiology of Diseases in Children Symposium in Chicago, IL. The talk addressed clinical and scientific questions and recently published data. At this time, among highly experienced and respected clinicians and researchers spanning relevant disciplines, there is substantial controversy regarding a role for inflammation in producing tics and obsessive-compulsive disorder. This commentary summarizes these controversies, discusses reasons for opposing views on best clinical practices, and concludes with suggestions for pathways forward.

Inflammation, Appetite and Food Intake in Older Hospitalized Patients

The effect of inflammation on appetite and food intake has been rarely studied in humans. In this study, we examined the association of C-reactive protein (CRP), as an inflammatory marker, with appetite and food intake among older hospitalized patients. A total of 200 older individuals, who were consecutively admitted to a geriatric acute care ward, participated in this prospective observational study. Appetite was evaluated using the Edmonton Symptom Assessment System (ESAS) and the Simplified Nutritional Appetite Questionnaire (SNAQ), respectively. Food intake was measured according to plate diagram method and participants were categorized as having food intake <75% and ≥75% of meals served. Nutritional status was evaluated using the Mini Nutritional Assessment Short Form (MNA-SF). In addition, serum CRP was analyzed and the levels >3.0 (mg/dL) were considered as moderate to severe inflammation. Of total population with mean age 81.4 ± 6.6 years (62.5% females), 51 (25.5%) had no inflammation and 88 (44.0%) and 61 (30.5%) had mild and moderate to severe inflammation, respectively. According to MNA-SF, 9.0% and 60.0% had normal nutritional status or a risk of malnutrition, respectively, whereas 31.0% were malnourished. Based on the SNAQ-appetite-question, 32.5% of the patients demonstrated poor and very poor appetite whereas 23.5% reported severe loss of appetite according to ESAS. Ninety-five (48.0%) of the participants had food intake <75% of the meals offered. Significant associations between SNAQ-appetite (p = 0.003) and ESAS-appetite (p = 0.013) scores and CRP levels were observed. In addition, significant differences were observed in CRP levels between intake ≥75% and <75% of meals served (p < 0.001). Furthermore, there were significant associations between appetite and nutritional status whereas malnourished older patients demonstrated a decreased appetite compared to those with normal nutritional status (p = 0.011). In a regression analysis, inflammation was the major independent risk factor for patients' appetite (p = 0.003) and food intake (p = 0.011) whereas other variables such as infection (p = 0.960), chronic inflammatory diseases (p = 0.371), age (p = 0.679) and gender (p = 0.447) do not show any impact on appetite. Our findings confirm that poor appetite and low food intake are associated with inflammation in older hospitalized patients, suggesting that inflammation may contribute an important aspect to the development of malnutrition in these patients.

A new cationic palladium(II) dithiocarbamate exhibits anti-inflammatory, analgesic, and antipyretic activities through inhibition of inflammatory mediators in in vivo models

Inflammation is being a protective mechanism of the body towards the injury. However, chronic and progressive inflammation may lead to some chronic diseases. Due to the serious unwanted effects associated with available drugs, new and safe anti-inflammatory agents are still required. Therefore, the present study was designed to investigate the anti-inflammatory, analgesics, and antipyretic properties of a new compound (4-benzylpiperidine-1-carbodithioato-κ2S,S')(1,4-bis-(diphenylphosphino)butane)palladium(II)chloride monohydrate (compound-1) in albino mice models. Compound-1 was characterized by elemental analysis, FT-IR, and multinuclear NMR spectroscopy. Initially, compound-1 was evaluated for cytotoxicity, anti-inflammatory, and analgesic activities by performing MTT assay, carrageenan-, histamine-, serotonin-, and CFA-induced paw edema, mechanical hyperalgesia, thermal hyperalgesia, and mechanical allodynia (0.1, 1, and 10 mg/kg, b.w). Antipyretic activity was evaluated in brewer's yeast-induced model. The pro-inflammatory cytokines were measured by using commercially available ELISA kits. Additionally, nitrite production, antioxidant enzymes, H&E staining, muscle activity and motor coordination, and kidney and liver function tests were also determined. The results demonstrated that compound-1 significantly inhibited inflammation, pain, and febrile responses in all models at a dose of 10 mg/kg without effecting viability of cells in vitro at concentrations up to 100 μM. Similarly, the data clearly demonstrated significant reduction in the pro-inflammatory cytokines and nitrite production while enhancing antioxidant enzymes. Furthermore, pretreatment with compound-1 did not produce any prominent side effect on kidney, liver, stomach, and muscles. These findings suggest that compound-1 has potent anti-inflammatory-, pain-, and pyrexia-relieving properties. Hence, compound-1 might be a potential candidate for the therapeutic management of chronic inflammation and pain.

Mindfulness training and systemic low-grade inflammation in stressed community adults: Evidence from two randomized controlled trials

Mindfulness interventions have garnered significant attention as a complementary health treatment for many physical and psychological conditions. While some research has shown that mindfulness training can decrease psychological and physiological stress responses, it remains unclear whether mindfulness training impacts inflammation—a predictor of poor health outcomes. In addition, little research has examined the active components of mindfulness that may drive health-related improvements. Here, we provide data from two 3-arm randomized controlled trials that examined the effect of mindfulness training on inflammation in stressed community adults. Specifically, we examined whether training individuals to have an accepting attitude towards present moment experiences is a key emotion regulation skill that can lead to decreases in inflammation. Both studies randomly assigned participants to one of three conditions: mindfulness training that taught both attention monitoring and acceptance skills (Monitor+Accept); mindfulness training teaching monitoring without the acceptance component (Monitor Only); or a control condition. Study 1 employed a novel 2-week smartphone-based intervention and Study 2 employed a standard 8-week Mindfulness-Based Stress Reduction (MBSR) intervention. We hypothesized that Monitor+Accept training would lead to reductions in the inflammatory biomarker C-Reactive Protein (CRP) compared to Monitor Only training and control groups. Contrary to this hypothesis, we found that Monitor+Accept mindfulness training did not lead to reductions in CRP. Exploratory analyses combining study subsamples, however, suggest that both mindfulness interventions may reduce CRP in populations at risk for systemic inflammation—midlife-to-older adults and individuals with high BMI. Overall, the present studies contribute significantly to the question of whether mindfulness interventions can reduce systemic markers of low-grade inflammation.

The associations between self-reported depression, self-reported chronic inflammatory conditions and cognitive abilities in UK Biobank

Background

Depression and chronic inflammatory medical conditions have been linked to impaired cognitive ability. However despite frequent comorbidity, their combined association with cognitive ability has rarely been examined.

Methods

This study examined associations between self-reported depression and chronic inflammatory diseases and their interaction with cognitive performance in 456,748 participants of the UK Biobank, adjusting for sociodemographic and lifestyle factors. Numbers with available data ranged from 94,899 to 453,208 depending on the cognitive test.

Results

Self-reported depression was associated with poorer performance compared to controls in several cognitive tests (fully adjusted models, reaction time: B = 6.08, 95% CI = 5.09, 7.07; pairs matching: incidence rate ratio = 1.02, 95% CI = 1.02, 1.03; Trail Making Test B: B = 1.37, 95% CI = 0.88, 1.87; Digit Symbol Substitution Test (DSST): B = −0.35, 95% CI = −0.44, −0.27). Self-reported chronic inflammatory conditions were associated with slower reaction time (B = 3.79, 95% CI = 2.81, 4.78) and lower DSST scores (B = −0.21, 95% CI = −0.30, −0.13). No interaction effects were observed.

Discussion

In this large, population-based study we provide evidence of lower cognitive performance in both depression and a comprehensive category of chronic inflammatory conditions. Results are consistent with additive effects of both types of disorder on cognitive ability. Clinicians should be aware of such effects, particularly as cognitive impairment is linked to poorer disease outcomes and quality of life.

In vivo direct relation of tau pathology with neuroinflammation in early Alzheimer's disease

OBJECTIVE

Neuronal damage and neuroinflammation are important events occurring in the brain of Alzheimer's disease (AD). The purpose of this study was to clarify in vivo mutual relationships among abnormal tau deposition, neuroinflammation and cognitive impairment in patients with early AD using positron emission tomography (PET) with [¹¹C]PBB3 and [¹¹C]DPA713.

METHODS

Twenty patients with early AD and 20 age-matched normal control (NC) subjects underwent a series of PET measurements with [¹¹C]PBB3 for tau aggregation and [¹¹C]DPA713 for microglial activation (neuroinflammation). Inter- and intrasubject comparisons were performed regarding the levels of [¹¹C]PBB3 binding potential (BP_ND) and [¹¹C]DPA713 BP_ND in the light of cognitive functions using statistical parametric mapping (SPM) and regions of interest (ROIs) method.

RESULTS

The [¹¹C]PBB3 BP_ND was greater in the temporo-parietal regions of AD patents than NC subjects, and a similar increasing pattern of [¹¹C]DPA713 BP_ND was observed in the same patients. Correlation analyses within the AD group showed a positive direct correlation between [¹¹C]PBB3 BP_ND and [¹¹C]DPA713 BP_ND in the parahippocampus. Pass analysis revealed that cognitive impairment was more likely linked to the level of the parahippocampal [¹¹C]PBB3 BP_ND than that of [¹¹C]DPA713 BP_ND.

CONCLUSIONS

The pattern of abnormal tau deposition was very similar to that of neuroinflammation in patients with early-stage AD. Specifically, the direct positive correlation of tau pathology with neuroinflammation in the parahippocampus suggests that neuronal damage in this region is closely associated with microglial activation. Consistently, tau aggregation in this region matters more than neuroinflammation regarding the cognitive deterioration in AD.

Independent and joint association of obesity and metabolic syndrome with depression and inflammation

OBJECTIVE

To investigate the separate and combined associations of obesity and metabolic syndrome (MetS) with depression and the role of inflammation.

METHOD

Depression was assessed with the Patient Health Questionnaire-9 (PHQ-9) and was defined with a cutpoint of ≥10. Obesity was defined as body mass index (BMI) ≥30 kg/m2 from measured height and weight. MetS was defined based on the American Heart Association consensus definition. Participants were divided into four groups: healthy normal weight (MHN), metabolically healthy obese (MHO), metabolically unhealthy normal weight (MUN), and metabolic unhealthy obese (MUO). C-Reactive protein was assessed in a subsample.

RESULTS

A total of 18,025 subjects were included in the analysis. Participants with MUO had the highest prevalence of depression compared with the MHN group (14.8% vs. 6.8, p < .001). While both obesity and MetS were independently associated with depression, there was a significant interaction between the two (p < .001), indicating that the associations of obesity and MetS with depression were synergistic. After adjusting for baseline characteristics, compared with the MHN group, the MUO group had the highest odds of depression (odds ratio [OR] = 2.30, 95% CI [2.03, 2.61]), followed by MHO group (OR = 1.51, 95% CI [1.30, 1.74]) and the MUN group (OR = 1.39, 95% CI [1.18, 1.64]). The MUO group also showed the highest level of C-reactive protein, and the latter partially mediated the effect between MUO and depressive symptoms (20.5% of the total effect).

CONCLUSION

Both obesity and MetS are associated with depression independent of each other, but when present together, these conditions have a synergistic association with depression. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Perceived relationship support moderates the association of contextual stress with inflammation among African Americans

We followed 402 African American young adults from ages 24 to 29, a period of emerging committed relationships, to examine the association of contextual stress (CS), for example, experiences of financial strain, victimization, and racial discrimination, with inflammation, and to test predictions that greater perceived relationship warmth and support (PRWS) at age 29 would moderate the association between earlier CS and inflammation, using a multiplex assessment of cytokines to construct an index of the ratio between predominantly proinflammatory cytokines versus predominantly anti-inflammatory cytokines. CS experienced at age 24 was associated with greater inflammation at age 29 in the full sample (b = .112, p = .004). PRWS at age 29 moderated the association of earlier CS with inflammation (b = -.114, p = .011), but there was no significant main effect of PRWS (b = -.053, p = .265). Finally, using an internal moderator approach, we compared the association of CS with inflammation among those not in a committed relationship to those in more or less supportive relationships, showing a significant and stronger association of CS with inflammation for those with low PRWS (-1 SD; b = .182, p < .001), a weaker and nonsignificant association of CS with inflammation among those with higher PRWS (+1 SD; b = -.002, p = .975), and an intermediate and nonsignificant association of CS with inflammation among those with no committed romantic relationship (b = .077, p = .227). Results were robust to number of cytokines included in the inflammation index. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Amyloid-β plaque formation and reactive gliosis are required for induction of cognitive deficits in App knock-in mouse models of Alzheimer's disease

BACKGROUND

Knock-in (KI) mouse models of Alzheimer's disease (AD) that endogenously overproduce Aβ without non-physiological overexpression of amyloid precursor protein (APP) provide important insights into the pathogenic mechanisms of AD. Previously, we reported that AppNL-G-F mice, which harbor three familial AD mutations (Swedish, Beyreuther/Iberian, and Arctic) exhibited emotional alterations before the onset of definitive cognitive deficits. To determine whether these mice exhibit deficits in learning and memory at more advanced ages, we compared the Morris water maze performance of AppNL-G-F and AppNL mice, which harbor only the Swedish mutation, with that of wild-type (WT) C57BL/6J mice at the age of 24 months. To correlate cognitive deficits and neuroinflammation, we also examined Aβ plaque formation and reactive gliosis in these mice.

RESULTS

In the Morris water maze, a spatial task, 24-month-old AppNL-G-F/NL-G-F mice exhibited significantly poorer spatial learning than WT mice during the hidden training sessions, but similarly to WT mice during the visible training sessions. Not surprisingly, AppNL-G-F/NL-G-F mice also exhibited spatial memory deficits both 1 and 7 days after the last training session. By contrast, 24-month-old AppNL/NL mice had intact spatial learning and memory relative to WT mice. Immunohistochemical analyses revealed that 24-month-old AppNL-G-F/NL-G-F mice developed massive Aβ plaques and reactive gliosis (microgliosis and astrocytosis) throughout the brain, including the cortex and hippocampus. By contrast, we observed no detectable brain pathology in AppNL/NL mice despite overproduction of human Aβ40 and Aβ42 in their brains.

CONCLUSIONS

Aβ plaque formation, followed by sustained neuroinflammation, is necessary for the induction of definitive cognitive deficits in App-KI mouse models of AD. Our data also indicate that introduction of the Swedish mutation alone in endogenous APP is not sufficient to produce either AD-related brain pathology or cognitive deficits in mice.

Sarcopenia and Its Implications for Metabolic Health

Sarcopenia not only affects the ability to lead an active lifestyle but also contributes to increased obesity, reduced quality of life, osteoporosis, and metabolic health, in part due to reduced locomotion economy and ease. On the other hand, increased obesity, decreased quality of life, and reduced metabolic health also contribute to sarcopenia. The purpose of this mini-review is to discuss the implications sarcopenia has for the development of obesity and comorbidities that occur with aging.

Neighborhood social cohesion is associated with lower levels of interleukin-6 in African American women

INTRODUCTION

Social cohesion is a positive neighborhood characteristic defined by feelings of connectedness and solidarity within a community. Studies have found significant associations between social cohesion and cardiovascular disease (CVD) risk factors and outcomes. Inflammation is one potential physiological pathway linking social cohesion to CVD development, but few studies have evaluated the relationship between social cohesion and inflammatory biomarkers. Prior research has also established that race and gender can modify the effects of neighborhood features, including social cohesion, on CVD risk factors and outcomes. This study aimed to examine the association between social cohesion and the inflammatory biomarkers interleukin-6 (IL-6) and C-reactive protein (CRP) in a cohort of African American and White women and men.

MATERIALS AND METHODS

Data from the Morehouse and Emory Team Up to Eliminate Health Disparities (META-Health) Study were used to assess the association between social cohesion and inflammation among African American (n = 203) and White (n = 176) adults from the Atlanta metropolitan area. Social cohesion was measured using the social cohesion subscale from the Neighborhood Health Questionnaire. Inflammatory biomarkers were measured from plasma frozen at -70 °C. Multivariable linear regression analyses were conducted, controlling for demographic, clinical, behavioral, and psychosocial factors sequentially. Interaction by race and gender was also examined.

RESULTS

In models adjusted for age, race, gender, and education, social cohesion was significantly associated with lower levels of IL-6 (β = -0.06, p = 0.03). There was a significant race × social cohesion interaction (p = 0.04), and a marginally significant gender × race × social cohesion interaction (p = 0.09). In race-stratified models controlling for age, gender, and education, social cohesion was associated with lower IL-6 levels in African Americans (β = -0.11, p = 0.01), but not Whites (β = 0.01, p = 0.91). In fully adjusted race- and gender-stratified models, social cohesion was associated with lower levels of IL-6 in African American women only (β = -0.15, p = 0.003). CRP was not associated with social cohesion in fully adjusted models.

CONCLUSION

The association between social cohesion and lower levels of IL-6 is modified by gender and race, with the strongest association emerging for African American women. Although the pathways through which social cohesion impacts inflammation remain unclear, it is possible that for African American women social cohesion manifests through neighborhood networks.

Old Friends, immunoregulation, and stress resilience

There is a considerable body of evidence indicating that chronic adverse experience, especially chronic psychosocial stress/trauma, represents a major risk factor for the development of many somatic and affective disorders, including inflammatory bowel disease (IBD) and posttraumatic stress disorder (PTSD). However, the mechanisms underlying the development of chronic stress-associated disorders are still in large part unknown, and current treatment and prevention strategies lack efficacy and reliability. A greater understanding of mechanisms involved in the development and persistence of chronic stress-induced disorders may lead to novel approaches to prevention and treatment of these disorders. In this review, we provide evidence indicating that increases in immune (re-)activity and inflammation, potentially promoted by a reduced exposure to immunoregulatory microorganisms ("Old Friends") in today's modern society, may be causal factors in mediating the vulnerability to development and persistence of stress-related pathologies. Moreover, we discuss strategies to increase immunoregulatory processes and attenuate inflammation, as for instance contact with immunoregulatory Old Friends, which appears to be a promising strategy to promote stress resilience and to prevent/treat chronic stress-related disorders.

Fto Deficiency Reduces Anxiety- and Depression-Like Behaviors in Mice via Alterations in Gut Microbiota

Depression and obesity have high concurrence within individuals, which may be explained by sharing the same risk factors, including disruption of the intestinal microbiota. However, evidence that delineated the causal connections is extremely scarce. Methods: Mice lacking fat mass- and obesity-associated gene (Fto) were generated. Fto-deficient and wild-type control mice were subjected to novel conditions with or without chronic unpredictable mild stress (CUMS) for 6 weeks. Some mice were treated with antibiotics via their drinking water for 6 weeks in order to deplete their microbiota. Behavioral tests were performed to evaluate anxiety- and depression-like behaviors. 16S rRNA amplicon and metagenomic sequencing were employed to analyse fecal microbiota. Plasma levels of inflammatory cytokines and lipopolysaccharides (LPS) were also compared. Results: Deletion of Fto led to lower body weight and decreased anxiety- and depression-like behaviors, Fto+/- mice were also less susceptible to stress stimulation, highlighting the essential role of Fto in pathogenesis of depression. With regard to gut microbiota, Fto deficiency mice harbored specific bacterial signature of suppressing inflammation, characterized with higher abundance of Lactobacillus, lower Porphyromonadaceae and Helicobacter. Critically, behavioral alterations of Fto+/- mice are mediated by shift in gut microbiota, as such changes can be partially attenuated using antibiotics. Exposure to CUMS increased serum IL-6 level while Fto deficiency reduced its level, which may be explained by a lower LPS concentration. Conclusion: Together, our findings uncover the roles of Fto on depression and provide insights into microbiota-related biological mechanisms underlying the association between obesity and depression.

Purple sweet potato color improves hippocampal insulin resistance via down-regulating SOCS3 and galectin-3 in high-fat diet mice

Hippocampal insulin resistance is the key factor in cognitive deficits. The obesity induces chronic inflammation and the inflammation molecules suppressors of cytokine signaling3 (SOCS3) and galectin-3 directly impair the insulin signaling. The anti-inflammation properties of purple sweet potato color (PSPC) prompted us to investigate the effect of PSPC on cognitive impairment associated with obesity. 60 C57BL/6 mice were randomly divided into four groups: normal, high fat diets (HFD), HFD+PSPC and PSPC. The mice were fed with the HFD or normal diet for 32 weeks. The PSPC (500 mg/kg/day) was administered via oral gavage from 21 to 32 weeks. The results showed the PSPC rectified the abnormal metabolism indexes induced by HFD, including ameliorated obesity, decreased the concentration of fasting blood glucose and improved the glucose tolerance. The Morris water maze test showed the PSPC alleviated the cognitive impairment in HFD mice. The PSPC decreased the expression of Iba1, tumor necrosis factor-α, interleukin-1β, SOCS3 and galectin-3 in hippocampus of HFD mice. The insulin signaling molecules including the p-IRS1 (Tyr608), PI3K p110α and p-AKT (Ser473) were detected and the PSPC treatment improved the insulin resistance in hippocampus of HFD mice. Furthermore, the PSPC increased Bcl-2, diminished the Bak and the cleaved-caspase3 in HFD mice hippocampus. These findings indicated that PSPC could be a potential treatment to improve the cognitive impairment associated with obesity.

Solid peripheral tumor leads to systemic inflammation, astrocyte activation and signs of behavioral despair in mice

Prevalence of depression is higher in patients with cancer than in the general population. Sustained systemic inflammation has been associated with depressive behavior and it has been reported that depressed patients commonly display alterations in their immune system. We previously showed that cancer in mice induces a systemic environment that promotes neutrophil activation and leukocytosis. We thus hypothesized that the peripheral systemic response to a solid tumor leads to endothelial activation, which may promote inflammatory changes in the brain with behavioral consequences. Using the Lewis lung carcinoma (LLC) model, we show that tumor growth induces a progressive increase in peripheral inflammation as observed by elevated interleukin-6 (IL-6). In behavioral studies, tumor-bearing mice showed no sign of motor, coordination or short term working memory deficits as assessed by rotarod, balance-beam, and novel object recognition tests. However, there was an impairment in the grip strength test and interestingly, an anxious and despair-like phenotype in the elevated plus-maze, and tail suspension tests, respectively. Immunostaining of perfused brains revealed fibrin accumulation in the vasculature with some leakage into the parenchyma, a process known to activate endothelial cells. Taken together, our results suggest that the inflamed and prothrombotic systemic environment created by the growth of a peripherally-located solid tumor induces endothelial activation, accumulation of fibrin in the brain and astrocyte activation, perhaps leading to depressive-like behavior.

The role of inflammation in core features of depression: Insights from paradigms using exogenously-induced inflammation

A wealth of evidence has implicated inflammation in the development of depression. Yet, the heterogeneous nature of depression has impeded efforts to understand, prevent, and treat the disease. The purpose of this integrative review is to summarize the connections between inflammation and established core features of depression that exhibit more homogeneity than the syndrome itself: exaggerated reactivity to negative information, altered reward processing, decreased cognitive control, and somatic syndrome. For each core feature, we first provide a brief overview of its relevance to depression and neurobiological underpinnings, and then review evidence investigating a potential role of inflammation. We focus primarily on findings from experimental paradigms of exogenously-induced inflammation. We conclude that inflammation likely plays a role in exaggerated reactivity to negative information, altered reward reactivity, and somatic symptoms. There is less evidence supporting an effect of inflammation on cognitive control as assessed by standard neuropsychological measures. Finally, we discuss implications for future research and recommendationsfor how to test the role of inflammation in the pathogenesis of heterogeneous psychiatric disorders.

Effects of psychological interventions on systemic levels of inflammatory biomarkers in humans: A systematic review and meta-analysis

The purpose of the present investigation was to systematically review randomized controlled trials examining the effects of psychological interventions on inflammatory biomarkers in adult populations and to quantitatively analyze those effects by meta-analysis. Two researchers independently searched key electronic databases, selected eligible publications, extracted data, and evaluated methodological quality. Nineteen randomized controlled trials examining a total of 1510 participants were included. The overall combined effect size from pre to post psychological intervention on pro-inflammatory biomarker levels was statistically significant, showing an attenuating effect, although of a small magnitude (s' g = 0.15, p = .008, CI [0.04-0.26]). However, this effect was not maintained into the follow-up period (g < -0.01, p = .964, CI [-0.19-0.18]). Looking at the individual biomarkers assessed across studies, only C-reactive protein (CRP) was found to significantly decrease following psychological intervention. A number of moderation analyses were conducted, none of which reached statistical significance. However, the numerically largest - and significant - within-group effect size was obtained for the group of studies that had preselected participants based on elevated psychological distress (g = 0.29, p = .047). In conclusion, psychological interventions appear efficacious in reducing pro-inflammatory biomarker levels. Future studies are recommended to carefully select individuals based on inflammatory (e.g., the presence of low-grade inflammation) and/or psychological (e.g., psychological distress) criteria.

Social stress during adolescence activates long-term microglia inflammation insult in reward processing nuclei

The experience of social stress during adolescence is associated with higher vulnerability to drug use. Increases in the acquisition of cocaine self-administration, in the escalation of cocaine-seeking behavior, and in the conditioned rewarding effects of cocaine have been observed in rodents exposed to repeated social defeat (RSD). In addition, prolonged or severe stress induces a proinflammatory state with microglial activation and increased cytokine production. The aim of the present work was to describe the long-term effects induced by RSD during adolescence on the neuroinflammatory response and synaptic structure by evaluating different glial and neuronal markers. In addition to an increase in the conditioned rewarding effects of cocaine, our results showed that RSD in adolescence produced inflammatory reactivity in microglia that is prolonged into adulthood, affecting astrocytes and neurons of two reward-processing areas of the brain (the prelimbic cortex, and the nucleus accumbens core). Considered as a whole these results suggest that social stress experience modulates vulnerability to suffer a loss of glia-supporting functions and neuronal functional synaptic density due to drug consumption in later life.

I do not want to suppress the natural process of inflammation: new insights on factors associated with non-adherence in rheumatoid arthritis

BACKGROUND

It is estimated that 50-70% of patients with rheumatoid arthritis (RA) are non-adherent to their recommended treatment. Non-adherent patients have a higher risk of not reaching an optimal clinical outcome. We explored factors associated with nonadherence from the patient's perspective.

METHODS

Four hundred and fifty-nine RA patients (346 (75.4%) females; mean age 63.0 ± 14.8 years) who failed to attend follow-up visits in two rheumatology centres were eligible to participate in a qualitative interview study. We used this strategy to identify patients who were potentially non-adherent to medicines and/or non-pharmacological interventions. By means of meaning condensation analysis, we identified new and some already well known insights to factors associated with non-adherence. We used the capability, opportunity, and motivation model of behaviour (COM-B) model as a frame of reference to classify the factors.

RESULTS

Forty-three of 131 patients (32.8%) who agreed to participate in the qualitative interviews were found to be non-adherent. New insights on factors associated with non-adherence included strong opinions of patients, such as pain being considered as an indicator of hard work and something to be proud of, or inflammation being a natural process that should not be suppressed; feeling not to be in expert's hands when being treated by a physician/health professional; the experience of excessive self-control over the treatment; and rheumatologists addressing only drugs and omitting non-pharmacological aspects. The COM-B model comprehensively covered the range of our findings.

CONCLUSIONS

The new insights on factors associated with non-adherence allow a better understanding of this phenomenon and can substantially enhance patient care by helping to develop targeted interventions.