A diet enriched with curcumin promotes resilience to chronic social defeat stress

Association between 29 food groups of diet quality questionnaire and perceived stress in Chinese adults: a prospective study from China health and nutrition survey

PURPOSE

Diet plays a fundamental role in promoting resilience against stress-related disorders. We aimed to examine the overall and sex-specific association between food groups and perceived stress in adults.

METHODS

We analyzed the prospective data of 7,434 adults who completed both the 2011 and 2015 surveys of the China Health and Nutrition Survey (CHNS). The Diet Quality Questionnaire (DQQ) was used to code all the food items of 2011 dietary intake into 29 food groups, and perceived stress in 2015 was measured using a 14-item perceived stress scale (PSS-14). Univariate analysis and logistic regression models were used to examine the relationship between food groups and perceived stress.

RESULTS

People who perceived a higher level of stress (PSS-14 total score > 25) made up 41.5% and 45.1% of the male and female groups, respectively (χ2 = 9.605, p = 0.002). Individuals with increased intake of food groups such as legumes, other vegetables, other fruits, yogurt, poultry, fish & seafood, fluid milk, and fruit juice were less likely to experience a higher level of psychological stress (OR range: 0.544-0.892, p < 0.05). Additionally, we found sex-specific associations between food groups and perceived stress. The difference in the proportion of food groups, such as fluid milk and fish & seafood, between the two stress groups in men was statistically significant (p < 0.025). In the female group, the distribution of eight food groups, like legumes and nuts & seeds, between the two stress groups was statistically significant (p < 0.025).

CONCLUSION

This study indicated that food groups were differentially associated with perceived stress.

Chronic Social Defeat Stress Gives Rise to Social Avoidance Through Fear Learning

Chronic social defeat stress (CSDS), a widely used rodent model of stress, reliably leads to decreased social interaction in stress susceptible animals. Here, we investigate a role for fear learning in this response using 129Sv/Ev mice, a strain that is more vulnerable to CSDS than the commonly used C57BL/6 strain. We first demonstrate that defeated 129Sv/Ev mice avoid a CD-1 mouse, but not a conspecific, indicating that motivation to socialize is intact in this strain. CD-1 avoidance is characterized by approach behavior that results in running in the opposite direction, activity that is consistent with a threat response. We next test whether CD-1 avoidance is subject to the same behavioral changes found in traditional models of Pavlovian fear conditioning. We find that associative learning occurs across 10 days CSDS, with defeated mice learning to associate the color of the CD-1 coat with threat. This leads to the gradual acquisition of avoidance behavior, a conditioned response that can be extinguished with 7 days of repeated social interaction testing (5 tests/day). Pairing a CD-1 with a tone leads to second-order conditioning, resulting in avoidance of an enclosure without a social target. Finally, we show that social interaction with a conspecific is a highly variable response in defeated mice that may reflect individual differences in generalization of fear to other social targets. Our data indicate that fear conditioning to a social target is a key component of CSDS, implicating the involvement of fear circuits in social avoidance.

Decoding the role of the gut microbiome in gut-brain axis, stress-resilience, or stress-susceptibility: A review

Increased exposure to stress is associated with stress-related disorders, including depression, anxiety, and neurodegenerative conditions. However, susceptibility to stress is not seen in every individual exposed to stress, and many of them exhibit resilience. Thus, developing resilience to stress could be a big breakthrough in stress-related disorders, with the potential to replace or act as an alternative to the available therapies. In this article, we have focused on the recent advancements in gut microbiome research and the potential role of the gut-brain axis (GBA) in developing resilience or susceptibility to stress. There might be a complex interaction between the autonomic nervous system (ANS), immune system, endocrine system, microbial metabolites, and bioactive lipids like short-chain fatty acids (SCFAs), neurotransmitters, and their metabolites that regulates the communication between the gut microbiota and the brain. High fiber intake, prebiotics, probiotics, plant supplements, and fecal microbiome transplant (FMT) could be beneficial against gut dysbiosis-associated brain disorders. These could promote the growth of SCFA-producing bacteria, thereby enhancing the gut barrier and reducing the gut inflammatory response, increase the expression of the claudin-2 protein associated with the gut barrier, and maintain the blood-brain barrier integrity by promoting the expression of tight junction proteins such as claudin-5. Their neuroprotective effects might also be related to enhancing the expression of brain-derived neurotrophic factor (BDNF) and glucagon-like peptide (GLP-1). Further investigations are needed in the field of the gut microbiome for the elucidation of the mechanisms by which gut dysbiosis contributes to the pathophysiology of neuropsychiatric disorders.

mGluR5 in hippocampal CA1 pyramidal neurons mediates stress-induced anxiety-like behavior

Pharmacological manipulation of mGluR5 has showed that mGluR5 is implicated in the pathophysiology of anxiety and mGluR5 has been proposed as a potential drug target for anxiety disorders. Nevertheless, the mechanism underlying the mGluR5 involvement in stress-induced anxiety-like behavior remains largely unknown. Here, we found that chronic restraint stress induced anxiety-like behavior and decreased the expression of mGluR5 in hippocampal CA1. Specific knockdown of mGluR5 in hippocampal CA1 pyramidal neurons produced anxiety-like behavior. Furthermore, both chronic restraint stress and mGluR5 knockdown impaired inhibitory synaptic inputs in hippocampal CA1 pyramidal neurons. Notably, positive allosteric modulator of mGluR5 rescued stress-induced anxiety-like behavior and restored the inhibitory synaptic inputs. These findings point to an essential role for mGluR5 in hippocampal CA1 pyramidal neurons in mediating stress-induced anxiety-like behavior.

Resilience by design: How nature, nurture, environment, and microbiome mitigate stress and allostatic load

Resilience to psychological stress is defined as adaption to challenging life experiences and not the absence of adverse life events. Determinants of resilience include personality traits, genetic/epigenetic modifications of genes involved in the stress response, cognitive and behavioral flexibility, secure attachment with a caregiver, social and community support systems, nutrition and exercise, and alignment of circadian rhythm to the natural light/dark cycle. Therefore, resilience is a dynamic and flexible process that continually evolves by the intersection of different domains in human’s life; biological, social, and psychological. The objective of this minireview is to summarize the existing knowledge about the multitude factors and molecular alterations that result from resilience to stress response. Given the multiple contributing factors in building resilience, we set out a goal to identify which factors were most supportive of a causal role by the current literature. We focused on resilience-related molecular alterations resulting from mind-body homeostasis in connection with psychosocial and environmental factors. We conclude that there is no one causal factor that differentiates a resilient person from a vulnerable one. Instead, building resilience requires an intricate network of positive experiences and a healthy lifestyle that contribute to a balanced mind-body connection. Therefore, a holistic approach must be adopted in future research on stress response to address the multiple elements that promote resilience and prevent illnesses and psychopathology related to stress allostatic load.

PET Imaging and Neurohistochemistry Reveal that Curcumin Attenuates Brain Hypometabolism and Hippocampal Damage Induced by Status Epilepticus in Rats

Numerous preclinical studies provide evidence that curcumin, a polyphenolic phytochemical extracted from Curcuma longa (turmeric) has neuroprotective, anti-inflammatory and antioxidant properties against various neurological disorders. Curcumin neuroprotective effects have been reported in different animal models of epilepsy, but its potential effect attenuating brain glucose hypometabolism, considered as an early marker of epileptogenesis that occurs during the silent period following status epilepticus (SE), still has not been addressed. To this end, we used the lithium-pilocarpine rat model to induce SE. Curcumin was administered orally (300 mg/kg/day, for 17 days). Brain glucose metabolism was evaluated in vivo by 2-deoxy-2-[¹⁸F]Fluoro-D-Glucose ([¹⁸F]FDG) positron emission tomography (PET). In addition, hippocampal integrity, neurodegeneration, microglia-mediated neuroinflammation, and reactive astrogliosis were evaluated as markers of brain damage. SE resulted in brain glucose hypometabolism accompanied by body weight (BW) loss, hippocampal neuronal damage, and neuroinflammation. Curcumin did not reduce the latency time to the SE onset, nor the mortality rate associated with SE. Nevertheless, it reduced the number of seizures, and in the surviving rats, curcumin protected BW and attenuated the short-term glucose brain hypometabolism as well as the signs of neuronal damage and neuroinflammation induced by the SE. Overall, our results support the potential adaptogen-like effects of curcumin attenuating key features of SE-induced brain damage.

Dulaglutide impedes depressive-like behavior persuaded by chronic social defeat stress model in male C57BL/6 mice: Implications on GLP-1R and cAMP/PKA signaling pathway in the hippocampus

AIM

There is a well-founded relation between bullying and depression, which may eventually lead to suicidal behavior. Repurposing of antidiabetic drugs for the treatment of depression started to glow, which open new horizons to introduce the antidiabetic medications as new treatment picks in depression. Dulaglutide has been approved as remedy of type 2 diabetes mellitus (T2DM). Consequently, our scope of work is to investigate the ability of dulaglutide to indulgence depression via deeply reconnoitering the Glucagon-like peptide-1 receptor and cAMP/PKA Signaling Pathway.

MATERIALS AND METHODS

Eighty mice were divided into two groups; one with and the other without the induction of chronic social defeat stress (CSDS). Each group was subdivided into two subsets; the first one was treated with saline for 42 days, while the other was treated with saline for 20 days, then with dulaglutide (0.6 mg/kg/week) for four weeks.

KEY FINDINGS

CSDS group showed a lessening in the social interaction ratio and sucrose consumption. They spent less exploration time in the open arms, and more time in the closed arms in elevated plus maze test as compared to controls. Furthermore, the CSDS group had a higher expression of NOD- like receptor protein-3 which explained the elevation in inflammatory biomarkers (IL-1β, IL-18, IL-6 and TNF-α) along with diminution in GLP-1R, cAMP/PKA levels. Treatment with dulaglutide markedly reversed the above-mentioned parameters via bolstering the GLP-1R/cAMP/PKA pathway.

SIGNIFICANCE

NLRP3 inflammasome activation expedites depression. Dulaglutide activates the GLP-1R/cAMP/PKA pathway, hence offering a novel therapeutic intervention to hinder depression.

Natural Phytochemicals for the Treatment of Major Depressive Disorder: A Mini-Review of Pre- and Clinical Studies

Major Depressive Disorder (MDD) is a common mental illness that causes significant disability and declining quality of life. An overlap of multiple factors can be involved in the pathophysiology of this mood disorder, including increased inflammation and oxidative stress, change in neurotransmitters, decreased brain-derived neurotrophic factor (BDNF), activation of the hypothalamicpituitary- adrenal (HPA) axis, and changes in the microbiota-gut-brain axis. Although the classic treatment for MDD is safe, it is far from ideal, with delay to start the best clinic, side effects, and a large number of non-responses or partial-responses. Therefore, other alternatives are being studied to improve depressive symptoms, and, among them, the role of phytochemicals in food stands out. This mini-review will discuss the main phytochemicals present in foods with clinical and preclinical studies showing benefits for MDD treatment. In addition, the main mechanisms of action that are being proposed for each of these compounds will be addressed.

Relationship between Vitamin Intake and Resilience Based on Sex in Middle-Aged and Older Japanese Adults: Results of the Shika Study

Epidemiological studies reported that resilience, generally regarded as the ability to manage stress in the face of adversity, correlates with mental health in middle-aged and older adults. Currently, there is limited information on eating habits that affect resilience. Therefore, this cross-sectional study investigated the relationship between vitamin intake and resilience based on sex in community-dwelling middle-aged and older individuals in Shika town, Ishikawa Prefecture, Japan. A total of 221 participants (106 men and 115 women) aged 40 years or older were included in the analysis. We assessed vitamin intake and resilience using a brief-type self-administered diet history questionnaire (BDHQ) and the resilience scale (RS), respectively. A two-way analysis of covariance (ANCOVA) revealed that higher intakes of β-carotene and vitamin K were associated with higher RS in women, but not in men. Furthermore, a multiple logistic regression analysis stratified by sex showed that β-carotene and vitamin K were significant independent variables for RS only in women. The present study suggests that higher intakes of β-carotene and vitamin K were associated with higher resilience among middle-aged and older women. The results obtained demonstrate that β-carotene and vitamin K intakes may enhance resilience by strengthening stress tolerance.

Intermittent voluntary wheel running promotes resilience to the negative consequences of repeated social defeat in mice

A novel approach to reduce the incidence of substance use disorders is to promote resilience to stress using environmental resources such as physical exercise. In the present study we test the hypothesis that Voluntary Wheel Running (VWR) during adolescence blocks the negative consequences of stress induced by intermittent repeated social defeat (IRSD). Four groups of adolescent male C57BL/6 mice were employed in the experiment; two groups were exposed to VWR (1 h, 3 days/week) from postnatal day (PND) 21 until the first social defeat (PND 47), while the remaining two groups did not have access to activity wheels (controls). On PND 47, 50, 53 and 56 mice, who had performed VWR, were exposed to an episode of social defeat by a resident aggressive mouse (VWR+IRSD group) or allowed to explore an empty cage (VWR+EXPL group). The same procedure was performed with control mice that had not undergone VWR (CONTROL+IRSD and CONTROL+EXPL groups). On PND 57, all the mice performed the Elevated Plus Maze (EPM), Hole-Board, Social Interaction, Tail Suspension and Splash tests. After an interval of 3 weeks, all mice underwent a conditioned place preference (CPP) procedure with 1 mg/kg of cocaine. Exposure to VWR prevented the negative consequences of social stress in the EPM, splash test and CPP, since the VWR+IRSD group did not display anxiety- or depression-like effects or the potentiation of cocaine reward observed in the Control+IRSD group. Our results support the idea that physical exercise promotes resilience to stress and represents an excellent target in drug abuse prevention.

Effect of the dietary intake of fish oil on psycho-social behavioral disorder caused by social-defeat stress

Exposure to psychosocial stress is a risk factor for human diseases such as depression. Social defeat stress (SDS) is a well-known rodent model of human psychosocial stress, and animals exposed to SDS show social avoidance behavior. Fish oil, which is rich in docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), is expected to decrease the risk of depressive disorders. In this study, we determined whether fish oil affects the social behavior of SDS-exposed mice and measured serotonin levels and expression of genes related to tryptophan (TRP) metabolism in the hippocampus. The experimental animals were fed a diet containing fish oil during SDS exposure. For the fish oil treatment, experimental mice were fed a diet containing fish oil at low (L-FO), middle (M-FO), and high (H-FO) concentrations. The control group was supplemented with an equivalent amount of canola oil (no fish oil: N-FO). After the SDS protocol, we performed a social interaction test and assessed the sociality of experimental mice. In the N-FO group, SDS-exposed mice showed negative social interactions compared with non-stressed mice. The L-FO and H-FO groups showed negative social interactions after SDS exposure; however, the M-FO group did not exhibit negative social behavior. The serotonin levels of SDS-exposed mice were lower than those of non-stressed mice in the N-FO group. In contrast with these results in the N-FO group, there was no difference in serotonin levels between SDS-exposed and non-stressed mice in the FO groups. In addition, the expression of genes related to TRP metabolism in SDS-exposed mice increased in the N-FO group, but not in the FO group. These results suggest that fish oil improves the psychosocial behavioral disorders caused by SDS. This improvement could be explained by the increase in serotonin synthesis in the hippocampus.

Impact of polyphenols on stress and anxiety: a systematic review of molecular mechanisms and clinical evidence

Mental health is a global public concern that contributes raising disability and premature death. Anxiety undertakes around 3.6% of the global population, while psychological stress is a condition associated to anxiety with a prevalence of 36.5%. Treatment for both mental conditions consist mainly of psychological therapy and pharmacotherapy, but the long-term drugs use can trigger adverse effects. Growing evidence shows the effect of specific food compounds on stress and anxiety treatment. The aim of this systematic review is to describe the molecular mechanisms related to dietary polyphenols administration from food matrix (considering food, juices or herbal/food extracts) and their effects on stress and/or anxiety, as well as review the available clinical evidence. Search was based on PRISMA Guidelines using peer-reviewed journal articles sourced from PubMed and Web of Science. A total of 38 articles were considered as eligible. The major effects for anxiety management were: reduction of oxidative stress and inflammation; HPA axis modulation; and regulation of some serotonergic/adrenergic pathways. There is a very limited evidence to conclude about the real effect of dietary polyphenols on stress. Although pharmacological treatment for mood disorders is essential, alternative therapies are necessary using non-pharmacological compounds to improve the long-term treatment effectiveness.

Nanocurcumin substantially alleviates noise stress-induced anxiety-like behavior: the roles of tight junctions and NMDA receptors in the hippocampus

Environmental noise stress affects non-auditory brain regions such as the hippocampus; an area of the brain implicated in cognition and emotion. Recent experimental data indicate that dysfunction of the blood-brain barrier (BBB) and overexpression of NMDA receptors may cause anxiety. In this experiment, we evaluated the effect of nanocurcumin on anxiety-like behavior and the expression of tight junctions and NMDA receptor subunits in the hippocampus of rats exposed to traffic noise. Forty rats were assigned to control (CON), stress (ST), nanocurcumin (NC), and nanocurcumin+stress (NC+ST) groups. Anxiety-like behavior was evaluated through an elevated zero maze apparatus. The gene expression of tight junctions and NMDA receptor subunits was examined by real-time PCR in the hippocampus. Statistical analysis showed that noise exposure developed anxiety-like behavior and elevated the corticosterone level in the ST group compared to the CON group. The nanocurcumin administration decreased the stress and anxiety in the NC+ST group compared to the ST animals. While the noise stress reduced the gene expression of tight junctions occludin, claudin-5, and ZO-1, the nanocurcumin administration increased them in the NC+ST animals. Furthermore, the noise stress elevated the gene expression of the NMDA receptor subunits GRIN1 and GRIN2B. The NC+ST animals showed a modification of these subunits compared to the ST animals. Our findings showed that noise exposure promotes stress and anxiety and impairs the NMDA receptor structure and BBB integrity. The nanocurcumin treatment displayed partly restored the destructive effects of noise exposure.

Formulated Curcumin Prevents Paclitaxel-Induced Peripheral Neuropathy through Reduction in Neuroinflammation by Modulation of α7 Nicotinic Acetylcholine Receptors

Paclitaxel is widely used in the treatment of various types of solid malignancies. Paclitaxel-induced peripheral neuropathy (PIPN) is often characterized by burning pain, cold, and mechanical allodynia in patients. Currently, specific pharmacological treatments against PIPN are lacking. Curcumin, a polyphenol of Curcuma longa, shows antioxidant, anti-inflammatory, and neuroprotective effects and has recently shown efficacy in the mitigation of various peripheral neuropathies. Here, we tested, for the first time, the therapeutic effect of 1.5% dietary curcumin and Meriva (a lecithin formulation of curcumin) in preventing the development of PIPN in C57BL/6J mice. Curcumin or Meriva treatment was initiated one week before injection of paclitaxel and continued throughout the study (21 days). Mechanical and cold sensitivity as well as locomotion/motivation were tested by the von Frey, acetone, and wheel-running tests, respectively. Additionally, sensory-nerve-action-potential (SNAP) amplitude by caudal-nerve electrical stimulation, electronic microscopy of the sciatic nerve, and inflammatory-protein quantification in DRG and the spinal cord were measured. Interestingly, a higher concentration of curcumin was observed in the spinal cord with the Meriva diet than the curcumin diet. Our results showed that paclitaxel-induced mechanical hypersensitivity was partially prevented by the curcumin diet but completely prevented by Meriva. Both the urcumin diet and the Meriva diet completely prevented cold hypersensitivity, the reduction in SNAP amplitude and reduced mitochondrial pathology in sciatic nerves observed in paclitaxel-treated mice. Paclitaxel-induced inflammation in the spinal cord was also prevented by the Meriva diet. In addition, an increase in α7 nAChRs mRNA, known for its anti-inflammatory effects, was also observed in the spinal cord with the Meriva diet in paclitaxel-treated mice. The use of the α7 nAChR antagonist and α7 nAChR KO mice showed, for the first time in vivo, that the anti-inflammatory effects of curcumin in peripheral neuropathy were mediated by these receptors. The results presented in this study represent an important advance in the understanding of the mechanism of action of curcumin in vivo. Taken together, our results show the therapeutic potential of curcumin in preventing the development of PIPN and further confirms the role of α7 nAChRs in the anti-inflammatory effects of curcumin.

Potential Role of Curcumin for the Treatment of Major Depressive Disorder

Curcumin is the major biologically active polyphenolic constituent in the turmeric plant (Curcuma longa) that has been shown to have antioxidant, anti-inflammatory, neuroprotective, anticancer, antimicrobial, and cardioprotective effects. Interest in curcumin as a treatment for mental health conditions has increased and there is an expanding body of preclinical and clinical research examining its antidepressant and anxiolytic effects. In this narrative review, human trials investigating the effects of curcumin for the treatment of depression or depressive symptoms are summarised. Using findings from in vitro, animal, and human trials, possible biological mechanisms associated with the antidepressant effects of curcumin are also explored. To increase the understanding of curcumin for the treatment of depression, directions for future research are proposed.

An overview on therapeutic role of Diferuloylmethane (Curcumin) in Azheimer’s disease and sleep disorders

Curcumin is widely used in spices in Asia. It has been widely explored for various diseases as therapeutic agent. Alzheimer’s disease (AD) is a neurodegenerative disease associated with dementia and cognitive disabilities. With the progression of disease, various changes appear in the brain cells that greatly affect the daily routine of the patient including sleep-wake disturbances. In the last few decades, extensive research has been carried out on this disease suggesting the development of non-steroidal anti-inflammatory drugs for its treatment. Since long, turmeric has been used in Asian countries as a home remedy for treating various ailments. Curcumin is an active ingredient isolated from the turmeric plant and is composed of curcuminoids. Because of its anti-inflammatory, antioxidant, anti-apoptotic and neuroprotective properties, curcumin can be safely administered to stop the progression of dementia and can be used for the development of such drugs that can reverse the neurotic damage caused by AD. This review article provides a comprehensive overview on the research carried out for AD using curcumin as active model drug.

Interplay of Nutrition and Psychoneuroendocrineimmune Modulation: Relevance for COVID-19 in BRICS Nations

The consequences of COVID-19 are not limited to physical health deterioration; the impact on neuropsychological well-being is also substantially reported. The inter-regulation of physical health and psychological well-being through the psychoneuroendocrineimmune (PNEI) axis has enduring consequences in susceptibility, treatment outcome as well as recuperation. The pandemic effects are upsetting the lifestyle, social interaction, and financial security; and also pose a threat through perceived fear. These consequences of COVID-19 also influence the PNEI system and wreck the prognosis. The nutritional status of individuals is also reported to have a determinative role in COVID-19 severity and convalescence. In addition to energetic demand, diet also provides precursor substances [amino acids (AAs), vitamins, etc.] for regulators of the PNEI axis such as neurotransmitters (NTs) and immunomodulators. Moreover, exaggerated immune response and recovery phase of COVID-19 demand additional nutrient intake; widening the gap of pre-existing undernourishment. Mushrooms, fresh fruits and vegetables, herbs and spices, and legumes are few of such readily available food ingredients which are rich in protein and also have medicinal benefits. BRICS nations have their influences on global development and are highly impacted by a large number of confirmed COVID-19 cases and deaths. The adequacy and access to healthcare are also low in BRICS nations as compared to the rest of the world. Attempt to combat the COVID-19 pandemic are praiseworthy in BRICS nations. However, large population sizes, high prevalence of undernourishment (PoU), and high incidence of mental health ailments in BRICS nations provide a suitable landscape for jeopardy of COVID-19. Therefore, appraising the interplay of nutrition and PNEI modulation especially in BRICS countries will provide better understanding; and will aid in combat COVID-19. It can be suggested that the monitoring will assist in designing adjunctive interventions through medical nutrition therapy and psychopsychiatric management.

Inhibition of boldenone-induced aggression in rats by curcumin: Targeting TLR4/MyD88/TRAF-6/NF-κB pathway

The illicit abuse of anabolic steroids is associated with brutal aggression, which represents a serious health hazard and social threat. Boldenone is commonly used for doping by athletes and adolescents for esthetic purposes and to enhance performance and endurance during competitions. However, the mechanistic pathways underlying boldenone-induced behavioral deviations and neuronal toxicity have not yet been elucidated. On the other hand, the natural polyphenol curcumin is appreciated for its relative safety, potent antioxidant activity, and anti-inflammatory properties. Therefore, the present study was initiated to explore the signaling pathways underlying boldenone-induced anxiety and aggression in rats, and the protective effects of curcumin. To achieve this aim, male Wistar albino rats were randomly distributed into control, curcumin (100 mg/kg in sesame oil, p.o., once daily), boldenone (5 mg/kg, intramuscular, once weekly), and combination groups. Rats were challenged across the open field, irritability, defensive aggression, and resident-intruder tests. The prefrontal cortex was used to assess serotonin level, oxidative stress markers, and mRNA expression of myeloid differentiation primary response gene (MyD88), TNFR-associated factor 6 (TRAF-6), tumor necrosis factor α (TNF-α), interleukin-1β (IL-1β), protein expression of toll-like receptor 4 (TLR4), and phosphorylated nuclear factor-κB transcription factor (NF-κB p65). Unprecedented, the current results showed that boldenone elicited aggression in rats accompanied by depleted serotonin, enhanced oxidative stress, and exaggerated inflammatory response via upregulation of TLR4/MyD88/TRAF-6/NF-κB pathway. Interestingly, curcumin mitigated boldenone-induced neurobehavioral disturbances in rats, normalized the oxidant/antioxidant balance, and suppressed TLR4/MyD88/TRAF-6/NF-κB pathway and its downstream proinflammatory signaling molecules TNF-α and IL-1β.

Co-Treatment With Verapamil and Curcumin Attenuates the Behavioral Alterations Observed in Williams-Beuren Syndrome Mice by Regulation of MAPK Pathway and Microglia Overexpression

Williams-Beuren syndrome (WBS) is a rare neurodevelopmental disorder characterized by a distinctive cognitive phenotype for which there are currently no effective treatments. We investigated the progression of behavioral deficits present in WBS complete deletion (CD) mice, after chronic treatment with curcumin, verapamil, and a combination of both. These compounds have been proven to have beneficial effects over different cognitive aspects of various murine models and, thus, may have neuroprotective effects in WBS. Treatment was administered orally dissolved in drinking water. A set of behavioral tests demonstrated the efficiency of combinatorial treatment. Some histological and molecular analyses were performed to analyze the effects of treatment and its underlying mechanism. CD mice showed an increased density of activated microglia in the motor cortex and CA1 hippocampal region, which was prevented by co-treatment. Behavioral improvement correlated with the molecular recovery of several affected pathways regarding MAPK signaling, in tight relation to the control of synaptic transmission, and inflammation. Therefore, the results show that co-treatment prevented behavioral deficits by recovering altered gene expression in the cortex of CD mice and reducing activated microglia. These findings unravel the mechanisms underlying the beneficial effects of this novel treatment on behavioral deficits observed in CD mice and suggest that the combination of curcumin and verapamil could be a potential candidate to treat the cognitive impairments in WBS patients.

Effects of Curcumin on Depression and Anxiety: A Narrative Review of the Recent Clinical Data

Depressive and anxiety disorders affect a significant proportion of the global population and constitute one of the highest disease burdens worldwide. Conventional pharmacological treatments are traditionally the first line of therapy for individuals affected by these conditions although these are only successful approximately half of the time and are often associated with undesirable side effects. This review describes the use of the natural substance curcumin as a potential alternative treatment of these mental disorders. With this in mind, we analyzed the effects of curcumin in eight clinical studies of depression and five studies of anxiety and assessed these using psychiatric symptom scores and molecular biomarker readouts.

Curcumin inhibits adverse psychological stress-induced proliferation and invasion of glioma cells via down-regulating the ERK/MAPK pathway

Curcumin is a natural polyphenol extracted from the rhizome of Curcuma that has an important antitumour effect, but its effect on adverse psychological stress‐induced tumour proliferation and invasion has not been reported to date. Here, we found that curcumin not only inhibited the growth of xenografts in chronically stressed nude mice, but also decreased the expression of matrix metalloproteinase (MMP)‐2/9 and CD147 in tumour tissues. Exogenous norepinephrine (NE) was used to stimulate glioma cells to simulate the stress environment in vitro, and it was found that curcumin inhibited the NE‐induced proliferation and invasion of glioma cells in a dose‐dependent manner. Further research found that the effects of NE on glioma cells could lead to the activation of the mitogen‐activated protein kinase (MAPK) signalling pathway through β‐adrenergic receptor, while curcumin suppressed the level of extracellular signal–regulated kinase (ERK)1/2 phosphorylation. In addition, blocking ERK1/2 expression with U0126 resulted in the down‐regulated expression of CD147, which further led to the decreased expression of MMP‐2 and MMP‐9. Curcumin could also inhibit the expression of cyclin D1/CDK4/6 and anti‐apoptotic protein Bcl‐2/Bcl‐XL induced by NE, and induced cell cycle changes and increased apoptosis. Therefore, curcumin may be a potential candidate drug for preventing and treating the progression of glioma induced by adverse psychological stress.

Prolonged chronic social defeat stress promotes less resilience and higher uniformity in depression-like behaviors in adult male mice

Chronic social defeat stress (CSDS) is widely applied to study of depression in rodents. 10-day CSDS was a most commonly employed paradigm but with high resilience ratio (∼30%), producing potential variation in depression-like behavioral symptoms. Whether prolonged period (21 days) of CSDS would promote less resilience and reduce behavioral variability remains unknown. We applied 10-day and 21-day CSDS paradigms to induce mouse model of depression and compared their resilience ratio and behavioral phenotypes. Mice under 21-day CSDS had significantly lower resilience ratio and greater changes in behavioral indicators relative to mice under 10-day CSDS. Behavioral indicators from 21-day CSDS paradigm had higher correlations and better prediction for susceptibility which indicating higher uniformity in behavioral phenotypes. Furthermore, a subset of behavioral indicators in 21-day CSDS had high prediction efficacy and should be first applied to screen susceptibility of CSDS. Thus, our study demonstrates that 21-day CSDS is a more robust paradigm inducing reliable depression-like behaviors relative to 10-day CSDS, and should be preferentially used in rodent studies of depression.

Modulation of the hypothalamic-pituitary-adrenal (HPA) axis by plants and phytonutrients: a systematic review of human trials

INTRODUCTION

The hypothalamic-pituitary-adrenal (HPA) axis plays a central role in the stress response. Plants, herbs, spices, and plant-based nutrients may influence HPA-axis activity.

OBJECTIVE

To evaluate randomised controlled, human trials assessing the effects of single plants or phytonutrients on HPA-axis related hormones.

METHODS

A systematic review of PubMed, Cochrane library, and the Cumulative Index to Nursing and Allied Health Literature was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Inclusion criteria comprised of human, randomised controlled studies with a control intervention examining the effects of a single herb, spice, plant, or extract on pre- and post-changes in blood, saliva, urine, or hair concentrations of cortisol, cortisone, corticotrophin-releasing hormone, or adrenocorticotropic hormone. Databases were searched from inception until October 2020.

RESULTS

Fifty-two studies were identified examining the effects of ashwagandha, Korean ginseng, St John's Wort, cannabidiol, Rhodiola rosea, curcumin, cherry juice, asparagus, Jiaogulan, Black cohosh, Siberian ginseng, Bacopa monnieri, blueberries, green tea, Caralluma fimbriata, cashew apple juice, melon, American ginseng, Ginkgo biloba, grape juice, grapefruit juice, rosella, hops, mangosteen, holy basil, and pomegranate juice. Due to significant variability in study designs, the effect of phytonutrients on HPA-axis activity in humans was unclear. The most consistent finding was a morning, cortisol-lowering effect from ashwagandha supplementation.

CONCLUSION

For most phytonutrients, the effects of supplementation on HPA-axis activity in humans is unclear. Before more definitive conclusions about the effects of phytonutrients on the HPA-axis can be made, further research is required.

The effects of Kctd12, an auxiliary subunit of GABAB receptor in dentate gyrus on behavioral response to chronic social defeat stress in mice

Adaptive responses to stress are critical to enhance physical and mental well-being, but excessive or prolonged stress may cause inadaptability and increase the risks of psychiatric disorders, such as depression. GABABR signaling is fundamental to brain function and has been identified in neuropsychiatric disorders. KCTD12 is a critical auxiliary subunit in GABABR signaling, but its role in mental disorders, such as depression is unclear. In the present study, we used a well-validated mice model, chronic social defeat stress (CSDS) to investigate behavioral responses to stress and explore the role of Kctd12 in stress response, as well as the relevant mechanisms. We found that CSDS increased the expression of Kctd12 in the dentate gyrus (DG), a subregion of hippocampus. Overexpression of Kctd12 in DG induced higher responsiveness to acute stress and increased vulnerability to social stress in mice, whereas knock-down of Kctd12 in DG prevented the social avoidance. Furthermore, an increased expression of GABAB receptor 2 (GB2) in the DG of CSDS-treated mice was observed, and CGP35348, an antagonist of GABABR, improved the stress-induced behavior responses along with suppressing the excess expression of Kctd12. In addition, Kctd12 regulated the excitability of granule cell in DG, and the stimulation of neuronal activity by silencing Kctd12 contributed to the antidepressant-like effect of fluoxetine. These findings identify that the Kctd12 in DG works as a critical mediator of stress responses, providing a promising therapeutic target in stress-related psychiatric disorders, including depression.

Nutritional interventions for promoting stress resilience: Recent progress using psychosocial stress models of rodents

Prevention of stress‐induced adverse effects is important for animals and humans to maintain their quality of life (QOL). Stress decreases the productivity of farm animals and induces abnormal behaviors, which is one of the major problems in animal welfare. In humans, stress increases the risk of mental illness which adversely impacts QOL. Stress is, thus, a common health problem for both animals and humans, and stress prevention and promotion of stress resilience could improve animal and human health and QOL. Among various stresses, psychosocial stress experienced by individuals is particularly difficult to prevent and it could, thus, prove beneficial to attempt to increase resilience to psychosocial stress. There exist a few critical interventions for promoting such resilience, environmental enrichment being one. However, this review describes recent progress in nutritional interventions that could confer resilience to psychosocial stress. The efficacy of this intervention is studied in the social defeat model mouse, which is a standard model for studying psychosocial stress. Several nutrients were found to rescue stress vulnerability using the models. Furthermore, probiotics and prebiotics became crucial dietary interventions for combating psychosocial stress. Collectively, dietary intake of appropriate nutrients will be more important for maintaining QOL in animals and humans.

Anti-stress effects of polyphenols: animal models and human trials

Polyphenols, a category of plant compounds that contain multiple phenol structural units, are widely distributed throughout the plant kingdom and have multiple benefits for human health including anti-obesity, anti-hyperglycemic, and anti-hyperlipidemic effects. Additionally, polyphenols have recently gained attention for their anti-stress effects. In this review article, we summarize physiological responses against exposure to stressors and discuss biomarkers for exposure to stressors that are widely used in animal studies and human trials. We also review commonly used animal models for evaluating anti-stress effects. Finally, we discuss recent findings related to the anti-stress effects of polyphenols evaluated in animal models and human trials, and their putative mechanisms. These emerging data require further investigation in scientific studies and human trials to evaluate the anti-stress effects of polyphenols and their potential use for the prevention of stress-related health problems.

Polyphenols selectively reverse early-life stress-induced behavioural, neurochemical and microbiota changes in the rat

There is a growing emphasis on the role of the microbiota-gut-brain axis as modulator of host behaviour and as therapeutic target for neuropsychiatric disorders. In addition, accumulating evidence suggests that early-life stress can exert long-lasting changes on the brain and microbiota, and this early adversity is associated with increased risk for developing depression in later life. The maternal separation (MS) model in rats is a robust paradigm to study the effects of early-life stress on the microbiota-gut-brain axis. Recently, we have shown that polyphenols, naturally occurring compounds associated with several health benefits, have anti-stress effects in in vitro models. In this study, we assess the therapeutic potential of a variety of both flavonoid and non-flavonoid polyphenols in reversing the impact of MS on behaviour and the microbiota-gut-brain axis. Rats underwent a dietary intervention with the naturally-derived polyphenols xanthohumol and quercetin, as well as with a phlorotannin extract for 8 weeks. Treatment with polyphenols prevented the depressive- and anxiety-like behaviours induced by MS, where xanthohumol effects were correlated with rescue of BDNF plasma levels. In addition, MS resulted in altered brain levels of 5-hydroxyindoleacetic acid (5-HIAA) and dopamine, accompanied by abnormal elevation of plasma corticosterone. Although polyphenols did not reverse neurotransmitter imbalance, xanthohumol normalised corticosterone levels in MS rats. Finally, we explored the impact of MS and polyphenolic diets on the gut microbiota. We observed profound changes in microbial composition and diversity produced by MS condition and by xanthohumol treatment. Moreover, functional prediction analysis revealed that MS results in altered enrichment of pathways associated with microbiota-brain interactions that are significantly reversed by xanthohumol treatment. These results suggest that naturally-derived polyphenols exert antidepressant-like effects in MS rats, which mechanisms could be potentially mediated by HPA regulation, BDNF levels rescue and modulation of the microbiota-gut-brain axis.

Adverse Childhood Experiences, Outcomes, and Interventions

Adverse childhood experiences (ACEs) are stressful or traumatic events that children experience before age 18 years. Studies have linked exposure to ACEs and negative health, and developmental and behavioral outcomes. Screening in pediatric medical settings provides a clear opportunity for early detection, intervention, and treatment. Providing anticipatory guidance on healthy relationships, sleep, exercise, nutrition, mindfulness, and nature is essential. Pediatric medical providers must screen and intervene. Primary care is the ideal setting for ACE screening because interacting with children and their families at regular intervals can allow patients and providers to develop a trusting relationship.

Oral treatment with Lactobacillus reuteri attenuates depressive-like behaviors and serotonin metabolism alterations induced by chronic social defeat stress

BACKGROUND

Alterations in bidirectional gut-brain interactions are believed to be involved in the pathogenesis of neuropsychiatric diseases. Considering the putative connections among gut microbiota, neural function, and behavior, this study investigated the potential of microbe-induced gut-to-brain signaling to modulate the impact of stress on depressive-like behaviors and serotonin metabolism.

METHODS

Depression-susceptible mice induced by chronic social defeat stress received oral treatment of either Lactobacillus reuteri 3 (L. reuteri 3) or vehicle for 28 days, and alterations in behavior and serotonin metabolism were assessed. 16S rRNA sequencing and gas chromatograph were employed to analyze the gut microbiota community and short-chain fatty acids (SCFAs).

RESULTS

Treatment with L. reuteri 3 ameliorated depressive-like behaviors, suppressed the increase in the relative abundances of Clostridiales and Adlercreutzia, improved the decrease in abundances of Lactobacillus, Allobaculum, and Sutterella induced by stress, and significantly increased the proportion of Bifidobacterium. L. reuteri 3 reduced the acetate and total SCFAs levels in the depression group. Blood and colon 5-HT were decreased in depressive-like mice but were significantly ameliorated after L. reuteri 3 treatment. Moreover, L. reuteri 3 administration increased the expression of enzymes involved in serotonin biosynthesis but suppressed that of the enzymes involved in tryptophan metabolism along the kynurenine pathway in colon and prefrontal cortex.

CONCLUSIONS

Despite the complexity of the gut microbiota, exposure to a single microbial strain L. reuteri 3 can protect against depressive-like behaviors induced by chronic social defeat stress. The anti-depressive effects of L. reuteri 3 were associated with improved gut microbiota and serotonin metabolism.

Social status and modern-type depression: A review

BACKGROUNDS

Social hierarchy is one of the most influential social structures employed by social species. While dominants in such hierarchies can preferentially access rich resources, subordinates are forced into lower social statuses and lifestyles with inferior resources. Previous studies have indicated that the social rank regulates social behaviors and emotion in a variety of species, whereby individual organisms live within the framework of their ranks. However, in human societies, people, particularly young men, who cannot accept their own social status may show social withdrawal behaviors such as hikikomori to avoid confronting their circumstances.

METHODS

This article reviews the neural mechanisms underlying social status identified in animal studies with rodents and primates, and assesses how social rank affects animal's social behaviors and emotion which may be relevant to modern type depression.

RESULTS

Several brain regions such as medial prefrontal cortex are implicated in the formation of animal's social status, which leads to the differences in vulnerability and resilience to social stress.

CONCLUSION

On the basis of these findings, we propose that physical interventions such as voluntary exercise, diet, transcranial direct current stimulation, and psychotherapy, rather than psychotropic drugs, may be useful therapeutic approaches for modern type depression, which is a typical example of social status conflict and a phenotype of adjustment disorder to the traditional hierarchical social order.