Diabesity and mood disorders: Multiple links through the microbiota-gut-brain axis

Improving dietary patterns in obese mice: Effects on body weight, adiposity, anhedonia-like behavior, pro-BDNF expression and 5-HT system

INTRODUCTION

The excessive fat accumulation in obesity, resulting from an unbalanced diet, can lead to metabolic and neurological disorders and increase the risk of developing anxiety and depression.

AIM

Assess the impact of dietary intervention (DI) on the serotonergic system, brain-derived neurotrophic factor (BDNF) expression and behaviors of obese mice.

METHODS

Male C57BL/6 mice, 5 weeks old, received a high-fat diet (HFD) for 10 weeks for the induction of obesity. After this period, for 8 weeks, half of these animals received a control diet (CD), group obese (OB) + control diet (OB + CD, n = 10), and another half continued being fed HFD, group obese + HFD (OB + HFD, n = 10). At the end of the eighth week of intervention, behavioral tests were performed (sucrose preference test, open field, novel object recognition, elevated plus maze and tail suspension). Body weight and food intake were assessed weekly. Visceral adiposity, the hippocampal and hypothalamic protein expression of BDNF, 5-HT1A (5-HT1A serotonin receptor) and TPH2 (key enzyme in serotonin synthesis), were evaluated after euthanasia.

RESULTS

The dietary intervention involved changing from a HFD to a CD over an 8-week period, effectively reduced body weight gain, adiposity, and anhedonia-like behavior. In the OB + HFD group, we saw a lower sucrose preference and shorter traveled distance in the open field, along with increased pro-BDNF expression in the hypothalamus compared to the OB + CD mice. However, the levels of TPH2 and 5-HT1A remained unchanged.

CONCLUSION

The HFD model induced both obesity and anhedonia, but the dietary intervention successfully improved these conditions.

Associated between cognition, brain-derived neurotrophic factor (BDNF) and macronutrients in normal and overweight postmenopausal women

BDNF is a protein associated with cognitive dysfunction. The aim of the study was to determine the relationship between BDNF and cognitive functions and the intake of macronutrients in postmenopausal women. For this purpose, 72 postmenopausal women were recruited to the study and divided into two subgroups: overweight/obese and normal weight. Using a 3-day food record, nutrition was assessed. The markers studied were the level of BDNF, which was determined from the venous blood serum collected from women, and selected cognitive functions. We observed that in the normal BMI group macronutrient intake was correlated with BDNF levels, and only total fat and carbohydrate intake were inversely correlated with BDNF levels. There were inverse correlations observed among selected parameters of cognitive functioning. In the Ov/Ob group, macronutrient intake correlated with the BDNF level for several variables, e.g. vice versa with total protein, fat and carbohydrate intake, as well as dietary cholesterol. It has also been noted that there are links between the BDNF factor and excessive body weight.

Long-term efficacy of washed microbiota transplantation in overweight patients

BACKGROUND

Faecal microbiota transplantation holds promise in mitigating fat accumulation and improving obesity. This study aimed to evaluate the long-term efficacy of washed microbiota transplantation (WMT) among overweight patients.

METHODS

The clinical data pertaining to the treatment of patients with WMT were collected retrospectively. Compared alterations in body mass index (BMI), blood glucose, blood lipids and blood pressure prior to and following WMT treatment. Comprehensive efficacy evaluation and atherosclerosis cardiovascular disease (ASCVD) grading evaluation were carried out, with an analysis of gut microbiota composition before and after WMT.

RESULTS

A total of 186 patients were included (80 overweight, 106 normal weight). WMT not only had the effect of improving overweight patients to the normal weight patients (p < .001), but also could significantly reduce BMI in the long term by restoring gut microbiota homeostasis (p < .001). In addition, the BMI improvement value of multi course was more significant than that of single course or double course. WMT had a significant ASCVD downgrade effect on the high-risk and medium-risk groups outside 1 year, while it did not increase the risk of upgrading ASCVD for low-risk group.

CONCLUSIONS

WMT could significantly reduce the BMI of overweight patients and still had an improvement effect in the long term.

Gut microbiome promotes mice recovery from stress-induced depression by rescuing hippocampal neurogenesis

Studies from rodents to primates and humans indicate that individuals vary in how resilient they are to stress, and understanding the basis of these variations may help improve treatments for depression. Here we explored the potential contribution of the gut microbiome to such variation. Mice were exposed to chronic unpredictable mild stress (CUMS) for 4 weeks then allowed to recover for 3 weeks, after which they were subjected to behavioral tests and categorized as showing low or high stress resilience. The two types of mouse were compared in terms of hippocampal gene expression using RNA sequencing, fecal microbiomes using 16S RNA sequencing, and extent of neurogenesis in the hippocampus using immunostaining of brain sections. Fecal microbiota were transplanted from either type of mouse into previously stress-exposed and stress-naïve animals, and the effects of the transplantation on stress-induced behaviors and neurogenesis in the hippocampus were examined. Finally, we blocked neurogenesis using temozolomide to explore the role of neurogenesis promoted by fecal microbiota transplantation in enhancing resilience to stress. Results showed that highly stress-resilient mice, but not those with low resilience, improved significantly on measures of anhedonia, behavioral despair, and anxiety after 3-week recovery from CUMS. Their feces showed greater abundance of Lactobacillus, Bifidobacterium and Romboutsia than feces from mice with low stress resilience, as well as lower abundance of Staphylococcus, Psychrobacter and Corynebacterium. Similarly, highly stress-resilient mice showed greater neurogenesis in hippocampus than animals with low stress resilience. Transplanting fecal microbiota from mice with high stress resilience into previously CUMS-exposed recipients rescued neurogenesis in hippocampus, facilitating recovery from stress-induced depression and cognitive decline. Blockade of neurogenesis with temozolomide abolished recovery of recipients from CUMS-induced depression and cognitive decline in mice transplanted with fecal microbiota from mice with high stress resilience. In conclusion, our results suggested that remodeling of the gut microbiome after stress may reverse stress-induced impairment of hippocampal neurogenesis and thereby promote recovery from stress-induced depression.

Study on toxicity responses and their mechanisms in Xenopus tropicalis long-term exposure to Shigella flexneri and ciprofloxacin

The abuse and overuse of antibiotics increased not only the exposure of aquatic animals to antibiotics but also the development of resistance in pathogenic bacteria. To investigate the effects and mechanisms of exposure, a long-term experiment lasting 120 days was conducted in which Xenopus tropicalis was exposed to single and combined stress factors of multiresistant pathogenic Shigella flexneri and ciprofloxacin (CIP). The intestinal oxidative stress, immune factors and flora, as well as the brain-gut axis correlation factors of X. tropicalis, were tracked to account for the response of aquatic animals to the exogenous pollutants. SOD activity and MDA content were significantly increased in stressed X. tropicalis (p < 0.001), while the levels of proinflammatory factors (IL-1β, IFN-γ) were significantly reduced (p < 0.01). The content of intestinal beneficial bacteria decreased and that of harmful bacteria increased in the intestinal flora of the stressed X. tropicalis (p < 0.001). These results suggested that S. flexneri and CIP disturbed the intestinal flora and caused oxidative damage in the host, and the body produced a series of responses, such as oxidative stress responses and regulation of the expression of immune factors, to maintain the balance of antioxidant inflammation. Significant changes in the expression of intestinal neurotransmitters (5-HT, CGRP) and brain peptides (BDNF, NCAM, NPY) (p < 0.05) also indicated that the brain-gut axis interaction was disrupted. In addition, although the coexisting CIP could reduce intestinal toxicity caused by S. flexneri, the amount of intestinal pathogenic bacteria Desulfovibrio increased significantly. Moreover, compared with the single exposure group, SOD activity, CAT activity and MDA content were significantly reduced in the dual exposure group. Therefore, the health risks of multiresistant pathogenic bacteria on the intestinal and brain-gut axis interaction should be given more attention, and the interaction of brain-gut axis is more important when antibiotics coexist.

Knockdown of IL4I1 Improved High Glucose-evoked Insulin Resistance in HepG2 Cells by Alleviating Inflammation and Lipotoxicity Through AHR Activation

Insulin resistance (IR) is one of the leading causes of Type 2 diabetes mellitus (T2DM). Inflammation, as a result of the disordered immune response, plays important roles in IR and T2DM. Interleukin-4-induced gene 1 (IL4I1) has been shown to regulate immune response and be involved in inflammation progress. However, there was little known about its roles in T2DM. Here, high glucose (HG)-treated HepG2 cells were used for T2DM investigation in vitro. Our results indicated that the expression of IL4I1 was up-regulated in peripheral blood samples of T2DM-patients and HG-induced HepG2 cells. The silencing of IL4I1 alleviated the HG-evoked IR through elevating the expressions of p-IRS1, p-AKT and GLUT4, and enhancing glucose consumption. Furthermore, IL4I1 knockdown inhibited inflammatory response by reducing the levels of inflammatory mediators, and suppressed the accumulation of lipid metabolites triglyceride (TG) and palmitate (PA) in HG-induced cells. Notably, IL4I1 expression was positively correlated with aryl hydrocarbon receptor (AHR) in peripheral blood samples of T2DM-patients. The silencing of IL4I1 inhibited the AHR signaling by reducing the HG-induced expressions of AHR and CYP1A1. Subsequent experiments confirmed that 2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD), an agonist of AHR, reversed the suppressive effects of IL4I1 knockdown on HG-caused inflammation, lipid metabolism and IR in cells. In conclusion, we found that the silencing of IL4I1 attenuated inflammation, lipid metabolism and IR in HG-induced cells via inhibiting AHR signaling, suggesting that IL4I1 might be a potential therapy target for T2DM.

The Role of the Adrenal-Gut-Brain Axis on Comorbid Depressive Disorder Development in Diabetes

Diabetic patients are more affected by depression than non-diabetics, and this is related to greater treatment resistance and associated with poorer outcomes. This increase in the prevalence of depression in diabetics is also related to hyperglycemia and hypercortisolism. In diabetics, the hyperactivity of the HPA axis occurs in parallel to gut dysbiosis, weakness of the intestinal permeability barrier, and high bacterial-product translocation into the bloodstream. Diabetes also induces an increase in the permeability of the blood-brain barrier (BBB) and Toll-like receptor 4 (TLR4) expression in the hippocampus. Furthermore, lipopolysaccharide (LPS)-induced depression behaviors and neuroinflammation are exacerbated in diabetic mice. In this context, we propose here that hypercortisolism, in association with gut dysbiosis, leads to an exacerbation of hippocampal neuroinflammation, glutamatergic transmission, and neuronal apoptosis, leading to the development and aggravation of depression and to resistance to treatment of this mood disorder in diabetic patients.

Systems biology approaches to identify potential targets and inhibitors of the intestinal microbiota to treat depression

Depression is a common mental disease, with some patients exhibiting ideas and behaviors such as self-harm and suicide. The drugs currently used to treat depression have not achieved good results. It has been reported that metabolites produced by intestinal microbiota affect the development of depression. In this study, core targets and core compounds were screened by specific algorithms in the database, and three-dimensional structures of these compounds and proteins were simulated by molecular docking and molecular dynamics software to further study the influence of intestinal microbiota metabolites on the pathogenesis of depression. By analyzing the RMSD gyration radius and RMSF, it was finally determined that NR1H4 had the best binding effect with genistein. Finally, according to Lipinski's five rules, equol, genistein, quercetin and glycocholic acid were identified as effective drugs for the treatment of depression. In conclusion, the intestinal microbiota can affect the development of depression through the metabolites equol, genistein and quercetin, which act on the critical targets of DPP4, CYP3A4, EP300, MGAM and NR1H4.

Shared biological mechanisms of depression and obesity: focus on adipokines and lipokines

Depression and obesity are both common disorders currently affecting public health, frequently occurring simultaneously within individuals, and the relationship between these disorders is bidirectional. The association between obesity and depression is highly co-morbid and tends to significantly exacerbate metabolic and related depressive symptoms. However, the neural mechanism under the mutual control of obesity and depression is largely inscrutable. This review focuses particularly on alterations in systems that may mechanistically explain the in vivo homeostatic regulation of the obesity and depression link, such as immune-inflammatory activation, gut microbiota, neuroplasticity, HPA axis dysregulation as well as neuroendocrine regulators of energy metabolism including adipocytokines and lipokines. In addition, the review summarizes potential and future treatments for obesity and depression and raises several questions that need to be answered in future research. This review will provide a comprehensive description and localization of the biological connection between obesity and depression to better understand the co-morbidity of obesity and depression.

Intranasal Nanotransferosomal Gel for Quercetin Brain Targeting: I. Optimization, Characterization, Brain Localization, and Cytotoxic Studies

Numerous neurological disorders have a pathophysiology that involves an increase in free radical production in the brain. Quercetin (QER) is a nutraceutical compound that shields the brain against oxidative stress-induced neurodegeneration. Nonetheless, its low oral bioavailability diminishes brain delivery. Therefore, the current study aimed to formulate QER-loaded transferosomal nanovesicles (QER-TFS) in situ gel for QER brain delivery via the intranasal route. This study explored the impacts of lipid amount, edge activator (EA) amount, and EA type on vesicle diameter, entrapment, and cumulative amount permeated through nasal mucosa (24 h). The optimum formulation was then integrated into a thermosensitive gel after its physical and morphological characteristics were assessed. Assessments of the optimized QER-TFS showed nanometric vesicles (171.4 ± 3.4 nm) with spherical shapes and adequate entrapment efficiency (78.2 ± 2.8%). The results of short-term stability and high zeta potential value (-32.6 ± 1.4 mV) of QER-TFS confirmed their high stability. Compared with the QER solution, the optimized QER-TFS in situ gel formulation exhibited sustained release behavior and augmented nasal mucosa permeability. CT scanning of rat brains demonstrated the buildup of gold nanoparticles (GNPs) in the brains of all treatment groups, with a greater level of GNPs noted in the rats given the transferosomal gel. Additionally, in vitro studies on PCS-200-014 cells revealed minimal cytotoxicity of QER-TFS in situ gel. Based on these results, the developed transferosomal nanovesicles may be a suitable nanocarrier for QER brain targeting through the intranasal route.

Unlocking the Secrets: Exploring the Biochemical Correlates of Suicidal Thoughts and Behaviors in Adults with Autism Spectrum Conditions

Involving 1 million people a year, suicide represents one of the major topics of psychiatric research. Despite the focus in recent years on neurobiological underpinnings, understanding and predicting suicide remains a challenge. Many sociodemographical risk factors and prognostic markers have been proposed but they have poor predictive accuracy. Biomarkers can provide essential information acting as predictive indicators, providing proof of treatment response and proposing potential targets while offering more assurance than psychological measures. In this framework, the aim of this study is to open the way in this field and evaluate the correlation between blood levels of serotonin, brain derived neurotrophic factor, tryptophan and its metabolites, IL-6 and homocysteine levels and suicidality. Blood samples were taken from 24 adults with autism, their first-degree relatives, and 24 controls. Biochemical parameters were measured with enzyme-linked immunosorbent assays. Suicidality was measured through selected items of the MOODS-SR. Here we confirm the link between suicidality and autism and provide more evidence regarding the association of suicidality with increased homocysteine (0.278) and IL-6 (0.487) levels and decreased tryptophan (-0.132) and kynurenic acid (-0.253) ones. Our results suggest a possible transnosographic association between these biochemical parameters and increased suicide risk.

Microbiota-gut-brain axis: relationships among the vagus nerve, gut microbiota, obesity, and diabetes

AIMS

The purpose of this review is to explore the interconnected pathways of the microbiota-gut-brain axis (MGBA), focusing on the roles of the vagus nerve and glucagon like peptide-1 in appetite control, and in the development of obesity and diabetes.

METHODS

Type 2 diabetes mellitus (T2DM) and obesity are metabolic disorders whose prevalence has significantly increased in recent decades and is expected to increase every year, to pandemic proportions. These two pathologies often coexist and have substantial public health implications. The term "diabesity" defines the pathophysiological connection between overweight and T2DM. The gut microbiota affects many aspects of the host. Beyond the regulation of intestinal functions and the activation of immune responses, the gut microbiota plays a role in central nervous system functions (i.e., mood, and psychiatric conditions associated with stress and memory) and is a central regulator of metabolism and appetite.

RESULTS

The MGBA involves pathways such as the autonomic and enteric nervous systems, the hypothalamic- pituitary-adrenal axis, the immune system, enteroendocrine cells, and microbial metabolites. Notably, the vagus nerve plays an essential role in eating behavior by modulating appetite and learning nutritional preferences.

CONCLUSIONS

Because of its enteroendocrine cell-mediated interaction with the gut microbiota, the vagus nerve may provide a potential pathway through which gut microorganisms influence host feeding behavior and metabolic control of physiological and pathological conditions.

A network perspective on the ecology of gut microbiota and progression of type 2 diabetes: Linkages to keystone taxa in a Mexican cohort

Introduction

The human gut microbiota (GM) is a dynamic system which ecological interactions among the community members affect the host metabolism. Understanding the principles that rule the bidirectional communication between GM and its host, is one of the most valuable enterprise for uncovering how bacterial ecology influences the clinical variables in the host.

Methods

Here, we used SparCC to infer association networks in 16S rRNA gene amplicon data from the GM of a cohort of Mexican patients with type 2 diabetes (T2D) in different stages: NG (normoglycemic), IFG (impaired fasting glucose), IGT (impaired glucose tolerance), IFG + IGT (impaired fasting glucose plus impaired glucose tolerance), T2D and T2D treated (T2D with a 5-year ongoing treatment).

Results

By exploring the network topology from the different stages of T2D, we observed that, as the disease progress, the networks lose the association between bacteria. It suggests that the microbial community becomes highly sensitive to perturbations in individuals with T2D. With the purpose to identify those genera that guide this transition, we computationally found keystone taxa (driver nodes) and core genera for a Mexican T2D cohort. Altogether, we suggest a set of genera driving the progress of the T2D in a Mexican cohort, among them Ruminococcaceae NK4A214 group, Ruminococcaceae UCG-010, Ruminococcaceae UCG-002, Ruminococcaceae UCG-005, Alistipes, Anaerostipes, and Terrisporobacter.

Discussion

Based on a network approach, this study suggests a set of genera that can serve as a potential biomarker to distinguish the distinct degree of advances in T2D for a Mexican cohort of patients. Beyond limiting our conclusion to one population, we present a computational pipeline to link ecological networks and clinical stages in T2D, and desirable aim to advance in the field of precision medicine.

Influence of Educational Level and Healthy Habits on the Prevalence of Diabesity in a Spanish Working Population

Background: Diabesity is a growing problem internationally. Taking into account the importance of physical activity and diet in its prevention and treatment, the objective of this study was to delve into the impact of healthy habits on diabesity. Methods: A descriptive, cross-sectional study was carried out in 386,924 Spanish adult workers. Obesity was determined according to eleven different formulas. Life habits were also valued; sociodemographic variables; and educational level; as well as analytical and clinical variables such as blood pressure and blood glucose levels. The association between the different variables was performed using the chi-square and the Student’s t-tests when the samples were independent. A multivariate analysis was performed using the multinomial logistic regression test by calculating the odds ratio and a 95% confidence interval. The Hosmer–Lemeshow goodness-of-fit test was also performed. Results: The overall prevalence of diabesity ranged between 0.3% (95% CI 0.3–0.4) when obesity was assessed according to the abdominal volume index and 8.3% (95% CI 8.2–8.4) when evaluated according to the CUN-BAE (Clínica Universitaria de Navarra Body Adiposity Estimator) formula. The prevalence of diabesity was also higher in workers with a non-heart-healthy diet and in those who did not exercise regularly. Conclusions: The most disadvantaged socioeconomic classes are those with the highest prevalence of diabesity. It is important to prioritise prevention in populations and communities with the most unfavourable social and environmental conditions to reduce the burden of diabesity.

Nutritional importance of tryptophan for improving treatment in depression and diabetes

The importance of nutrients in our diet is becoming increasingly recognized. From the viewpoint of protein synthesis and other physiologic and metabolic functions, all amino acids are important, but some of these amino acids are not synthesized endogenously. This subset, called essential amino acids, comprise dietarily indispensable nutrients. Tryptophan, an essential amino acid, is the sole precursor of neuronal as well as peripheral serotonin (5-hydroxytryptamine). Its systemic or oral administration increases serotonin synthesis because tryptophan hydroxylase, the rate-limiting enzyme of 5-hydroxytryptamine biosynthesis, is physiologically unsaturated with its substrate. Central serotonin is implicated in a number of psychiatric illnesses, including depression, and in responses to stress. Acting peripherally, serotonin affects vasoconstriction, intestinal motility, control of T cell–mediated immunity, and liver and pancreatic functions. Depression and diabetes are 2 highly prevalent diseases that often coexist. There is evidence that occurrence of depression is 2–3 times higher in people with diabetes mellitus. A comorbid condition of diabetes and depression worsens the treatment and increases risk for death. Stress, known for its causal role in depression, can also enhance risk for diabetes. Stress-induced decreases in the circulating levels of tryptophan can impair brain and pancreatic serotonin-dependent functions to precipitate these diseases. The importance of tryptophan supplementation for improving therapeutic intervention in depression and diabetes is the focus of this article. A deficiency of this essential amino acid may enhance risk for depression as well as diabetes, and can also weaken treatment efficacy of medicinal compounds for treating these diseases. Guidelines for optimal levels of circulating tryptophan can help if supplements of this amino acid can improve treatment efficacy.

The microbiota-gut-brain axis and its modulation in the therapy of depression: comparison of efficacy of conventional drugs and traditional Chinese medicine approaches

Depression is a common and severe mental disease that places a heavy burden on human society, which can lead to decreased cognitive function, energy loss, insomnia, and even suicide. Although medication plays an important role in improving the symptoms of depression, approximately one third of people with depression do not significantly benefit from medication and experience various adverse reactions. Recently, increasing evidence has shown that gut microbes play an important role in the occurrence and development of depression. There have been illuminating studies previously conducted on the relationship between antidepressant chemicals, traditional Chinese medicine, and the microbiota-gut-brain axis (MGBA). Therefore, in this review, we summarize the role of the MGBA in the occurrence and development of depression, especially the important role of the MGBA in the mechanism of action of antidepressants. Modulation of the MGBA is proposed to enhance the efficacy of antidepressant drugs and reduce their side effects and disease recurrence, so as to provide a new method for the treatment of depression.

Amelioration of Non-Alcoholic Steatohepatitis by Atractylodes macrocephala Polysaccharide, Chlorogenic Acid, and Geniposide Combination Is Associated With Reducing Endotoxin Gut Leakage

Gut-derived lipopolysaccharide (LPS) leaking through the dysfunctional intestinal barrier contributes to the onset of non-alcoholic steatohepatitis (NASH) by triggering inflammation in the liver. In the present study, a combination consisting of Atractylodes macrocephala polysaccharide (A), chlorogenic acid (C), and geniposide (G) (together, ACG), was shown to ameliorate NASH in mice and reduce hepatic LPS signaling and endotoxemia without decreasing the abundance of identified Gram-negative bacteria through restoring the intestinal tight junctions. Our data indicated that inhibition of LPS gut leakage by the ACG combination contributed to its amelioration of NASH.

Fasting in mood disorders and its potential therapeutic aspects -narrative review

Introduction: Fasting is defined as a period of voluntary abstinence from eating food for religious, therapeutic or political reasons, which is associated with a reduction in the supply of sources (kilocalories) to the body. There are different types of fasting, including short, long or intermittent fasting. It has been shown that the use of different types of fasting can influence the occurrence of mood disorders. The aim of this review was to search for the relationship between the use of fasting and mood disorders and its potential use as a therapeutic method.

Material and method: The available literature was reviewed by searching the PubMed and Google Scholar databases using the following keywords: fasting, intermittent fasting, mood disorders, depression, Ramadan, for studies listed from database inception to November 2021.

Results: A review of the collected scientific articles indicates that the dietary restrictions, including both daily restriction of caloric consumption and the use of intermittent fasting (IF), has potentially numerous health benefits in the co-treatment of mental diseases. However, due to conflicting results, further clinical trials in mentally ill people should be conducted. It is worth remembering that among patients with mental illnesses there are somatically ill. IF in these people may require additional nutritional modifications or discontinuation of therapy.

Conclusions: Dietary restriction and fasting are promising methods in co-therapy of mood disorders treatment. However, implementing therapy needs earlier individual evaluation of their benefits and risk, the same as patient’s feasibility of implementing this type of intervention.

Palmitoylethanolamide dampens neuroinflammation and anxiety-like behavior in obese mice

High-fat diet (HFD) consumption leads to obesity and a chronic state of low-grade inflammation, named metainflammation. Notably, metainflammation contributes to neuroinflammation due to the increased levels of circulating free fatty acids and cytokines. It indicates a strict interplay between peripheral and central counterparts in the pathogenic mechanisms of obesity-related mood disorders. In this context, the impairment of internal hypothalamic circuitry runs in tandem with the alteration of other brain areas associated with emotional processing (i.e., hippocampus and amygdala). Palmitoylethanolamide (PEA), an endogenous lipid mediator belonging to the N-acylethanolamines family, has been extensively studied for its pleiotropic effects both at central and peripheral level. Our study aimed to elucidate PEA capability in limiting obesity-induced anxiety-like behavior and neuroinflammation-related features in an experimental model of HFD-fed obese mice. PEA treatment promoted an improvement in anxiety-like behavior of obese mice and the systemic inflammation, reducing serum pro-inflammatory mediators (i.e., TNF-α, IL-1β, MCP-1, LPS). In the amygdala, PEA increased dopamine turnover, as well as GABA levels. PEA also counteracted the overactivation of HPA axis, reducing the expression of hypothalamic corticotropin-releasing hormone and its type 1 receptor. Moreover, PEA attenuated the immunoreactivity of Iba-1 and GFAP and reduced pro-inflammatory pathways and cytokine production in both the hypothalamus and hippocampus. This finding, together with the reduced transcription of mast cell markers (chymase 1 and tryptase β2) in the hippocampus, indicated the weakening of immune cell activation underlying the neuroprotective effect of PEA. Obesity-driven neuroinflammation was also associated with the disruption of blood-brain barrier (BBB) in the hippocampus. PEA limited the albumin extravasation and restored tight junction transcription modified by HFD. To gain mechanistic insight, we designed an in vitro model of metabolic injury using human neuroblastoma SH-SY5Y cells insulted by a mix of glucosamine and glucose. Here, PEA directly counteracted inflammation and mitochondrial dysfunction in a PPAR-α-dependent manner since the pharmacological blockade of the receptor reverted its effects. Our results strengthen the therapeutic potential of PEA in obesity-related neuropsychiatric comorbidities, controlling neuroinflammation, BBB disruption, and neurotransmitter imbalance involved in behavioral dysfunctions.

Rumination and Worry Selectively Modulate Total Calorie Consumption within an Online, Nudge Tactic Paradigm

Rumination and worry, collectively referred to as perseverative cognition, have been implicated in the increased engagement of several health risk behaviours. The current study aimed to investigate the potential influencing role of these repetitive negative thought cognitions in an online snack paradigm. Participants were randomly assigned to either an even condition (a 3:3 ratio of ≤101 kcal and >201 kcal snacks) or an uneven condition (a 4:2 ratio in favour of ≤101 kcal snacks). Upon the presentation of six images of sweet treats, participants were asked to choose the snack they most wanted to consume “right now”, before completing the Ultra-Brief Penn State Worry Questionnaire (UB-PSWQ) and the brief (5-item) Ruminative Response Scale (RRS). The results showed that the reduced availability of higher calorie snacks significantly improved both snack choice and total calorie consumption. However, despite rumination and worry having no influence on the snack type chosen, higher levels of rumination still led to significantly higher overall calorie consumption. Although, contrary to predictions, higher levels of worry conversely led to significantly lower overall calorie consumption. This study adds to the growing work in the role of perseverative cognition and food consumption, which may aid in informing public health strategies. Further exploration is needed to assess whether rumination directly induces unhealthy eating behaviours or simply exacerbates them.

Structural basis of neuropeptide Y signaling through Y1 receptor

Neuropeptide Y (NPY) is highly abundant in the brain and involved in various physiological processes related to food intake and anxiety, as well as human diseases such as obesity and cancer. However, the molecular details of the interactions between NPY and its receptors are poorly understood. Here, we report a cryo-electron microscopy structure of the NPY-bound neuropeptide Y1 receptor (Y1R) in complex with Gi1 protein. The NPY C-terminal segment forming the extended conformation binds deep into the Y1R transmembrane core, where the amidated C-terminal residue Y36 of NPY is located at the base of the ligand-binding pocket. Furthermore, the helical region and two N-terminal residues of NPY interact with Y1R extracellular loops, contributing to the high affinity of NPY for Y1R. The structural analysis of NPY-bound Y1R and mutagenesis studies provide molecular insights into the activation mechanism of Y1R upon NPY binding.

SNAP25 mutation disrupts metabolic homeostasis, steroid hormone production and central neurobehavior

OBJECTIVE

SNAP-25 is one of the key proteins involved in formation of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complexes that are at the core of hormonal secretion and synaptic transmission. Altered expression or function of SNAP-25 can contribute to the development of neuropsychiatric and metabolic disease. A dominant negative (DN) I67T missense mutation in the b-isoform of SNAP-25 (DN-SNAP25mut) mice leads to abnormal interactions within the SNARE complex and impaired exocytotic vesicle recycling, yet the significance of this mutation to any association between the central nervous system and metabolic homeostasis is unknown.

METHODS

Here we explored aspects of metabolism, steroid hormone production and neurobehavior of DN-SNAP25mut mice.

RESULTS

DN-SNAP25mut mice displayed enhanced insulin function through increased Akt phosphorylation, alongside increased adrenal and gonadal hormone production. In addition, increased anxiety behavior and beigeing of white adipose tissue with increased energy expenditure were observed in mutants.

CONCLUSIONS

Our results show that SNAP25 plays an important role in bridging central neurological systems with peripheral metabolic homeostasis, and provide potential insights between metabolic disease and neuropsychiatric disorders in humans.

Strategies for circadian rhythm disturbances and related psychiatric disorders: A new cue based on plant polysaccharides and intestinal microbiota

Circadian rhythm is essential to human physiological homeostasis and health. The oscillation of host circadian rhythm affects the composition and function of intestinal microbiota, meanwhile, the normal operation of host...

Shared metabolic and neuroimmune mechanisms underlying Type 2 Diabetes Mellitus and Major Depressive Disorder

Type 2 Diabetes Mellitus (T2DM) is a chronic metabolic disease with symptoms that go beyond the domain of glucose metabolism. In fact, research has shown that T2DM is accompanied by neurodegeneration and neuroinflammation. Interestingly, Major Depressive Disorder (MDD), a mood disorder characterized mainly by depressed mood and anhedonia is a key feature of T2DM. A body of evidence demonstrates that there are many shared neuroimmune mechanisms underlying the pathophysiology of T2DM and MDD. Therefore, here we review the state-of-art regarding the underlying factors common to both T2DM and MDD. Furthermore, we briefly discuss how depressive symptoms in diabetic patients could be tackled by using novel therapeutic approaches uncovered by these shared mechanisms. Understanding the comorbidity of depression in diabetic patients is essential to fully address T2DM pathophysiology and treatment.

Antidepressant effects of curcumin-coated iron oxide nanoparticles in a rat model of depression

The antidepressant effect of curcumin-coated iron oxide nanoparticles (Cur-IONPs) was investigated in the current study using depression rat model induced by reserpine. IONPs were synthesized by curcumin as a reducing agent producing Cur-IONPs. Rats were divided into control, depression rat model, and depressed rats treated with Cur-IONPs. After treatment rat behavior was evaluated using forced swimming test (FST). Serotonin (5-HT), norepinephrine (NE), dopamine (DA), monoamine oxidase (MAO), acetylcholinesterase (AchE), Na⁺, K⁺, ATPase, lipid peroxidation (MDA), reduced glutathione (GSH), glutathione-s-transferase (GST) and nitric oxide (NO) were measured in the cortex and hippocampus. In depressed rats, FST showed increased immobilization time and reduced swimming time. This was associated with a significant decrease in 5-HT, NE, DA and GSH and a significant increase in MDA and NO levels and GST, MAO, AchE and Na⁺, K⁺, ATPase activities in the cortex and hippocampus. Treatment with Cur-NONPs for two weeks increased the swimming time reduced the immobility time, and elevated 5-HT, NE and DA levels. Cur-IONPs attenuated the oxidative stress induced by reserpine and restored the MAO, AchE and Na⁺, K⁺, ATPase. The present green method used curcumin in the IONPs synthesis and has several merits; obtaining nanoform of iron oxide, increasing the bioavailability of curcumin and reducing the oxidative stress induced by iron. The present antidepressant effect of Cur-IONPs could be attributed to the ability of Cur-IONPs to restore monoamine neurotransmitter levels by increasing their synthesis and reducing their metabolism. In addition, the antioxidant activity of curcumin prevented oxidative stress in the depressed rats.

The Influence of Probiotic Supplementation on Depressive Symptoms, Inflammation, and Oxidative Stress Parameters and Fecal Microbiota in Patients with Depression Depending on Metabolic Syndrome Comorbidity-PRO-DEMET Randomized Study Protocol

There is a huge need to search for new treatment options and potential biomarkers of therapeutic response to antidepressant treatment. Depression and metabolic syndrome often coexist, while a pathophysiological overlap, including microbiota changes, may play a role. The paper presents a study protocol that aims to assess the effect of probiotic supplementation on symptoms of depression, anxiety and stress, metabolic parameters, inflammatory and oxidative stress markers, as well as fecal microbiota in adult patients with depressive disorders depending on the co-occurrence of metabolic syndrome. The trial will be a four-arm, parallel-group, prospective, randomized, double-blind, controlled design that will include 200 participants and will last 20 weeks (ClinicalTrials.gov identifier: NCT04756544). The probiotic preparation will contain Lactobacillus helveticus Rosell^®-52, Bifidobacterium longum Rosell^®-175. We will assess the level of depression, anxiety and stress, quality of life, blood pressure, body mass index and waist circumference, white blood cells count, serum levels of C-reactive protein, high-density lipoprotein (HDL) cholesterol, triglycerides, fasting glucose, fecal microbiota composition and the level of some fecal microbiota metabolites, as well as serum inflammatory markers and oxidative stress parameters. The proposed trial may establish a safe and easy-to-use adjunctive treatment option in a subpopulation of depressive patients only partially responsive to pharmacologic therapy.

Adiposity in Depression or Depression in Adiposity? The Role of Immune-Inflammatory-Microbial Overlap

Some of the most common and debilitating conditions are metabolic disorders (metabolic syndrome and non-alcoholic fatty liver disease) and depression. These conditions are also exacerbated by the fact that they often co-occur. Although the exact mechanisms underlying such relationships are poorly known, antipsychotic medication and antidepressant use, diet and physical activity, and lifestyle factors are believed to play a role; however, their high co-occurrence rate suggests a possible pathophysiological overlap. This paper reviews several possible bases for this overlap, including hypothalamic-pituitary-adrenal axis dysregulation, immune alterations with chronic inflammation, and oxidative stress. While it is entirely possible that changes in the microbiota may play a role in each of them, interventions based on the implementation of dietary and other lifestyle changes, supplementation with prebiotics or probiotics and faecal microbiota transplantation have failed to achieve conclusive results. A better characterization of the above associations may allow a more targeted approach to the treatment of both depressive and metabolic disorders. The paper also presents several practical applications for future studies.

Does Gut-Microbiome Interaction Protect against Obesity and Obesity-Associated Metabolic Disorders?

More research has recently focused on the role of the gut microbiota in the development or course of numerous diseases, including non-communicable diseases. As obesity remains prevalent, the question arises as to what microbial changes are associated with increased obesity prevalence and what kind of prevention and treatment approaches it could provide. Moreover, the influence of the gut-brain axis on obesity is also crucial, since it can affect metabolism and food intake. The quantitative and qualitative changes in the microbiota composition are called dysbiosis; however, in view of the current knowledge, it is difficult to conclude which microbial imbalances are adverse or beneficial. Increased numbers of pathological microorganisms were observed among patients with obesity and comorbidities associated with it, such as diabetes, cardiovascular disease, and insulin resistance. Our review provides current knowledge regarding changes in the intestinal microbiota associated with obesity and obesity-associated comorbidities. Nevertheless, given that dietary patterns and nutrients are two of the factors affecting the intestinal microbiota, we also discuss the role of different dietary approaches, vitamins, and minerals in the shaping of the intestinal microbiota.

The Holobiont Blindspot: Relating Host-Microbiome Interactions to Cognitive Biases and the Concept of the "Umwelt"

Cognitive biases can lead to misinterpretations of human and non-human biology and behavior. The concept of the Umwelt describes phylogenetic contrasts in the sensory realms of different species and has important implications for evolutionary studies of cognition (including biases) and social behavior. It has recently been suggested that the microbiome (the diverse network of microorganisms in a given environment, including those within a host organism such as humans) has an influential role in host behavior and health. In this paper, we discuss the host’s microbiome in relation to cognitive biases and the concept of the Umwelt. Failing to consider the role of host–microbiome (collectively termed a “holobiont”) interactions in a given behavior, may underpin a potentially important cognitive bias – which we refer to as the Holobiont Blindspot. We also suggest that microbially mediated behavioral responses could augment our understanding of the Umwelt. For example, the potential role of the microbiome in perception and action could be an important component of the system that gives rise to the Umwelt. We also discuss whether microbial symbionts could be considered in System 1 thinking – that is, decisions driven by perception, intuition and associative memory. Recognizing Holobiont Blindspots and considering the microbiome as a key factor in the Umwelt and System 1 thinking has the potential to advance studies of cognition. Furthermore, investigating Holobiont Blindspots could have important implications for our understanding of social behaviors and mental health. Indeed, the way we think about how we think may need to be revisited.

Therapeutic potential of natural products against atherosclerosis: Targeting on gut microbiota

Gut microbiota (GM) has emerged as an essential and integral factor for maintaining human health and affecting pathological outcomes. Metagenomics and metabolomics characterization have furthered gut metagenome's understanding and unveiled that deviation of specific GM community members and GM-dependent metabolites imbalance orchestrate metabolic or cardiovascular diseases (CVDs). Restoring GM ecosystem with nutraceutical supplements keenly prebiotics and probiotics relatively decreases CVDs incidence and overall mortality. In Atherosclerosis, commensal and pathogenic gut microbes correlate with atherogenesis events. GM-dependent metabolites-trimethylamine N-oxide and short-chain fatty acids regulate atherosclerosis-related metabolic processes in opposite patterns to affect atherosclerosis outcomes. Therefore, GM might be a potential therapeutic target for atherosclerosis. In atherogenic animal models, natural products with cardioprotective properties could modulate the GM ecosystem by revitalizing healthier GM phylotypes and abrogating proatherogenic metabolites, paving future research paths for clinical therapeutics.

Type 2 Diabetes Mellitus Associated with Obesity (Diabesity). The Central Role of Gut Microbiota and Its Translational Applications

Obesity is a condition of rising prevalence worldwide, with important socioeconomic implications, being considered as a growing public health concern. Frequently, obesity brings other complications in addition to itself—like Type 2 Diabetes Mellitus (T2DM)—sharing origin, risk factors and pathophysiological mechanisms. In this context, some authors have decided to include both conditions as a unique entity known as “diabesity”. In fact, understanding diabesity as a single disease is possible to maximise the benefits from therapies received in these patients. Gut microbiota plays a key role in individual’s health, and their alterations, either in its composition or derived products are related to a wide range of metabolic disorders like T2DM and obesity. The present work aims to collect the different changes reported in gut microbiota in patients with T2DM associated with obesity and their possible role in the onset, development, and establishment of the disease. Moreover, current research lines to modulate gut microbiota and the potential clinical translation derived from the knowledge of this system will also be reviewed, which may provide support for a better clinical management of such a complex condition.

A dynamic mouse peptidome landscape reveals probiotic modulation of the gut-brain axis

Certain probiotics have beneficial effects on the function of the central nervous system through modulation of the gut-brain axis. Here, we describe a dynamic landscape of the peptidome across multiple brain regions, modulated by oral administration of different probiotic species over various times. The spatiotemporal and strain-specific changes of the brain peptidome correlated with the composition of the gut microbiome. The hippocampus exhibited the most sensitive response to probiotic treatment. The administration of heat-killed probiotics altered the hippocampus peptidome but did not substantially change the gut microbiome. We developed a literature-mining algorithm to link the neuropeptides altered by probiotics with potential functional roles. We validated the probiotic-regulated role of corticotropin-releasing hormone by monitoring the hypothalamic-pituitary-adrenal axis, the prenatal stress–induced hyperactivity of which was attenuated by probiotics treatment. Our findings provide evidence for modulation of the brain peptidome by probiotics and provide a resource for further studies of the gut-brain axis and probiotic therapies.

Crosstalk between the microbiota-gut-brain axis and depression

Nutritional and microbiological psychiatry, especially the contribution of the gut microbiota to depression, has become a promising research field over the past several decades. An imbalance in the "microbiota-gut-brain axis", which reflects the constant bidirectional communication between the central nervous system and the gastrointestinal tract, has been used as a hypothesis to interpret the pathogenesis of depression. Alterations in gut microbiota composition could increase the permeability of the gut barrier, activate systemic inflammation and immune responses, regulate the release and efficacy of monoamine neurotransmitters, alter the activity and function of the hypothalamic-pituitary-adrenal (HPA) axis, and modify the abundance of brain-derived neurotrophic factor (BDNF), eventually leading to depression. In this article, we review changes in gut microbiota in depressive states, the association between these changes and depression-like behavior, the potential mechanism linking gut microbiota disruptions and depression, and preliminary attempts at using gut microbiota intervention for the treatment of depression. In summary, although the link between gut microbiota and depression and the potential mechanism have been discussed, a more detailed mechanistic understanding is needed to fully realize the importance of the microbiota-gut-brain axis in depression. Future efforts should aim to determine the potential causative mechanisms, which will require further animal and clinical research as well as the development of analytical approaches.

Anhedonia induced by high-fat diet in mice depends on gut microbiota and leptin

Objectives: Imbalanced nutrition and obesity are risk factors for depression, a relationship that in rodents can be modeled by depression-like behavior in response to high-fat diet (HFD). In this work, we examined the role of the intestinal microbiota and the adipocytokine leptin as potential mediators of the effects of HFD to induce anhedonia-like behavior and reduce self-care in mice.Methods: Male mice were fed a control diet or HFD (60 kJ% from fat) for a period of 4 weeks, after which behavioral tests and molecular analyses (gut microbiome composition, intestinal metabolome, fecal fatty acids, plasma hormone levels) were performed. The role of the intestinal microbiota was addressed by selective depletion of gut bacteria with a combination of non-absorbable antibiotics, while the implication of leptin was examined by the use of leptin-deficient ob/ob mice.Results: Antibiotic treatment reduced the HFD-induced weight gain and adiposity and prevented HFD-induced anhedonia-like behavior and self-care reduction. These effects were associated with a decrease in fecal fatty acids and intestinal microbiota-related metabolites including short-chain fatty acids, glucose and amino acids. Gut microbiota depletion suppressed the HFD-induced rise of plasma leptin, and the circulating leptin levels correlated with the anhedonia-like behavior and reduced self-care caused by HFD. The anhedonic effect of HFD was absent in leptin-deficient ob/ob mice although these animals gained more weight and adiposity in response to HFD than wild-type mice.Discussion: The results indicate that anhedonia-like behavior induced by HFD in mice depends on the intestinal microbiome and involves leptin as a signaling hormone.

Gut microbiota in surgical and critically ill patients

Microbiota-defined as a collection of microbial organisms colonising different parts of the human body-is now recognised as a pivotal element of human health, and explains a large part of the variance in the phenotypic expression of many diseases. A reduction in microbiota diversity, and replacement of normal microbes with non-commensal, pathogenic or more virulent microbes in the gastrointestinal tract-also known as gut dysbiosis-is now considered to play a causal role in the pathogenesis of many acute and chronic diseases. Results from animal and human studies suggest that dysbiosis is linked to cardiovascular and metabolic disease through changes to microbiota-derived metabolites, including trimethylamine-N-oxide and short-chain fatty acids. Dysbiosis can occur within hours of surgery or the onset of critical illness, even without the administration of antibiotics. These pathological changes in microbiota may contribute to important clinical outcomes, including surgical infection, bowel anastomotic leaks, acute kidney injury, respiratory failure and brain injury. As a strategy to reduce dysbiosis, the use of probiotics (live bacterial cultures that confer health benefits) or synbiotics (probiotic in combination with food that encourages the growth of gut commensal bacteria) in surgical and critically ill patients has been increasingly reported to confer important clinical benefits, including a reduction in ventilator-associated pneumonia, bacteraemia and length of hospital stay, in small randomised controlled trials. However, the best strategy to modulate dysbiosis or counteract its potential harms remains uncertain and requires investigation by a well-designed, adequately powered, randomised controlled trial.

The potential mechanism of postoperative cognitive dysfunction in older people

Postoperative cognitive dysfunction (POCD) is a common disorder following surgery, which seriously threatens the quality of patients' life, especially the older people. Accumulating attention has been paid to POCD worldwide in pace with the popularization of anesthesia/surgery. The development of medical humanities and rehabilitation medicine sets higher demands on accurate diagnosis and safe treatment system of POCD. Although the research on POCD is in full swing, underlying pathogenesis is still inconclusive due to these conflicting results and controversial evidence. Generally, POCD is closely related to neuropsychiatric diseases such as dementia, depression and Alzheimer's disease in molecular pathways. Researchers have come up with various hypotheses to reveal the mechanisms of POCD, including neuroinflammation, oxidative stress, autophagy disorder, impaired synaptic function, lacking neurotrophic support, etc. Recent work focused on molecular mechanism of POCD in older people has been thoroughly reviewed and summed up here, concerning the changes of peripheral circulation, pathological pathways of central nervous system (CNS), the microbiota-gut-brain axis and the related brain regions. Accordingly, this article provides a better perspective to understand the development situation of POCD in older people, which is conductive to uncover the pathological mechanism and exploit reasonable treatment strategy of POCD.

Human Milk Microbiome and Maternal Postnatal Psychosocial Distress

Human milk contains many bioactive components, including bacteria, which are transferred to the developing infant through breastfeeding. Milk bacteria appear to, amongst others, originate from the maternal gut. A mother’s postnatal psychosocial distress may alter maternal gut microbiota, which in turn may affect the bacteria present in milk. The aim of this study was to explore whether maternal postnatal psychosocial distress was related to alterations in the relative abundances of specific bacteria and to milk microbial diversity. Healthy mothers (N = 77; N = 51 with complete data) collected breast milk samples at 2, 6, and 12 weeks postpartum and filled in mood questionnaires on experienced stress, anxiety, and depressive symptoms at 6 weeks postpartum. A metataxonomic approach (16S rRNA gene sequencing (region V3 and V4) using Illumina MiSeq technology) was used to assess bacterial abundances and diversity. For the group as a whole, an increase in diversity of the milk bacterial community was observed during the first 3 months of breastfeeding (Shannon index). This general increase in diversity appears to be explained by an increase of Lactobacillus and other minor genera, together with a decrease in Staphylococcus. With respect to psychological distress and milk microbial composition, no significant differences in the relative abundance of major bacterial genera were detected between women with high (N = 13) and low (N = 13) psychosocial distress. However, progressive and distinct changes in the content of Firmicutes, Proteobacteria, and Bacteroidetes at the phylum level and Acinetobacter, Flavobacterium, and Lactobacillus at the genera level were observed in milk samples of women with low psychosocial distress. With respect to milk microbial diversity, high maternal psychosocial distress, compared to low maternal psychosocial distress, was related to significantly lower bacterial diversity in milk at 3 months post-delivery. Anxiety, stress, and depressive symptoms separately were unrelated to specific bacterial profiles. The current study suggests a potential relation between maternal psychosocial distress and milk microbiota, providing first evidence of a possible mechanism through which post-partum psychological symptoms may affect infant development and health.

Intranasal Neuropeptide Y Blunts Lipopolysaccharide-Evoked Sickness Behavior but Not the Immune Response in Mice

Neuropeptide Y (NPY) has been demonstrated to exert stress buffering effects and promote resilience. Non-invasive intranasal (IN) application of NPY to rodents is able to mitigate traumatic stress-induced behavioral changes as well as dysfunction of the hypothalamic-pituitary-adrenal (HPA) axis. However, it is unknown whether IN NPY could prevent the behavioral, pro-inflammatory and neurochemical responses to peripheral immune activation by the Toll-like receptor 4 (TLR4) stimulant lipopolysaccharide (LPS). Therefore, we analyzed the effects of IN NPY (100 μg) on the behavioral sickness response (reduced locomotion and exploration) and the underlying molecular mechanisms, 3 h and 21 h after intraperitoneal injections of LPS (0.03 mg/kg) in male C57BL/6N mice. The acute behavioral sickness response was significantly dampened by pretreatment with IN NPY 3 h after LPS injection. This effect was accompanied by diminished weight loss and lowered plasma corticosterone (CORT) levels 21 h after LPS injection. In contrast, acute circulating cytokine levels and hypothalamic cytokine mRNA expression remained unaltered by IN NPY, which indicates that the peripheral and cerebral immune response to LPS was left undisturbed. Our findings are in agreement with the reported activity of NPY to dampen the response of the HPA axis to stress. We propose that IN NPY ablates sickness behavior at a site beyond the peripheral and cerebral cytokine response, an action that is associated with reduced activity of the HPA axis as determined by decreased plasma CORT.These results indicate that IN NPY administration may be relevant to the management of neuropsychiatric disorders arising from immune-induced neuroendocrine dysfunction.

Proteomic analysis of the intestine reveals SNARE-mediated immunoregulatory and amino acid absorption perturbations in a rat model of depression

AIMS

To clarify the role of the gut-brain axis in depression.

MAIN METHODS

We used the iTRAQ technique to identify differential proteins in the intestine of the rat model of chronic unpredictable mild stress (CUMS)-induced depression. Significant differential proteins were subjected to Gene Ontology (GO) functional annotations and KEGG pathway enrichment analysis. Key proteins were validated at the mRNA and protein levels. The levels of cytokines in the intestine, serum and hypothalamus were examined by ELISA. HPLC-UV was used to detect the levels of amino acids.

KEY FINDINGS

In the rat intestine, 349 differential proteins (209 downregulated, 140 upregulated) were identified. GO analysis indicated that "protein complex assembly" was the first-ranked biological process. SNARE complex components, including SNAP23, VAMP3 and VAMP8, were increased at the mRNA levels, while only VAMP3 and VAMP8 were also upregulated at the protein level. TNFα, IL6 and IL1β were upregulated in the CUMS rat intestine, while TNFα was decreased in the serum and hypothalamus. IL1β was decreased in the serum. "Protein digestion and absorption" was the most significantly enriched KEGG pathway, involving 5 differential proteins: SLC9A3, ANPEP, LAT1, ASCT2 and B⁰AT1. Glutamine, glycine and aspartic acid were perturbed in the CUMS rat intestine.

SIGNIFICANCE

Our findings suggest that CUMS enhances the adaptive immune response in the intestine through ER-phagosome pathway mediated by SNARE complex and disturb absorption of amino acids. It advances our understanding of the role of gut-brain axis in depression and provides a potential therapeutic target for the disease.

Hericium erinaceus Improves Mood and Sleep Disorders in Patients Affected by Overweight or Obesity: Could Circulating Pro-BDNF and BDNF Be Potential Biomarkers?

Epidemiological data indicate that subjects affected by obesity have an increased risk of developing mood disorders. The relationship between obesity and mood disorders is bidirectional. We assessed whether a Hericium erinaceus treatment improved depression, anxiety, sleep, and binge eating disorders after 8 weeks of supplementation in subjects affected by overweight or obesity under a low calorie diet regimen. Looking for a possible clinical biomarker, we assessed the serum balance between brain-derived neurotrophic factor (BDNF) and its precursor pro-BDNF before and after H. erinaceus supplementation. Seventy-seven volunteers affected by overweight or obesity were recruited at the offices of the Department of Preventive Medicine, Luigi Devoto Clinic of Work, Obesity Centre, at the IRCCS Foundation Policlinico Hospital of Milan (Italy). Patients were recruited only if they had a mood and/or sleep disorder and/or were binge eating as evaluated through self-assessment questionnaires. We used two different enzyme-linked immunosorbent assays kits to discriminate circulating levels of pro-BDNF and BDNF. Eight weeks of oral H. erinaceus supplementation decreased depression, anxiety, and sleep disorders. H. erinaceus supplementation improved mood disorders of a depressive-anxious nature and the quality of the nocturnal rest. H. erinaceus increased circulating pro-BDNF levels without any significant change in BDNF circulating levels.