Increased Oxidative Stress in the Prefrontal Cortex as a Shared Feature of Depressive- and PTSD-Like Syndromes: Effects of a Standardized Herbal Antioxidant

The power of Punica granatum: A natural remedy for oxidative stress and inflammation; a narrative review

ETHNOPHARMACOLOGICAL RELEVANCE

Pomegranate 'Punica granatum' offers multiple health benefits, including managing hypertension, dyslipidemia, hyperglycemia, insulin resistance, and enhancing wound healing and infection resistance, thanks to its potent antioxidant and anti-inflammatory properties. It has been symbolized by life, health, femininity, fecundity, and spirituality.

AIM OF THE STUDY

Although laboratory and animal studies have been conducted on the healing effects of pomegranate, there needs to be a comprehensive review on its anti-oxidative and anti-inflammatory effects in chronic disorders. We aim to provide a comprehensive review of these effects based on in-vitro, in-vivo, and clinical studies conducted in managing various disorders.

MATERIALS AND METHODS

A comprehensive search of in-vitro, in-vivo, and clinical findings of pomegranate and its derivatives focusing on the highly qualified original studies and systematic reviews are carried out in valid international web databases, including Web of Science, PubMed, Scopus, and Cochrane Library.

RESULTS

Relevant studies have demonstrated that pomegranate and its derivatives can modulate the expression and activity of several genes, enzymes, and receptors through influencing oxidative stress and inflammation pathways. Different parts of pomegranate; roots, bark, blossoms, fruits, and leaves contain various bioactive compounds, such as polyphenols, flavonoids, anthocyanins, and ellagitannins, that have preventive and therapeutic effects against many disorders such as cardiovascular diseases, diabetes, neurological diseases, and cancers without any serious adverse effects.

CONCLUSIONS

Most recent scientific evidence indicates that all parts of the pomegranate can be helpful in treating a wide range of chronic disorders due to its anti-oxidative and anti-inflammatory activities. Since the safety of pomegranate fruit, juice, and extracts is established, further investigations can be designed by targeting its active antioxidant and anti-inflammatory constituents to discover new drugs.

Early Handling Exerts Anxiolytic Effects and Alters Brain Mitochondrial Dynamics in Adult High Anxiety Mice

Early handling (EH), the brief separation of pups from their mother during early life, has been shown to exert beneficial effects. However, the impact of EH in a high anxiety background as well as the role of brain mitochondria in shaping EH-driven responses remain elusive.Here, we used a high (HAB) vs. normal (NAB) anxiety-related behavior mouse model to study how EH affects pup and dam behavior in divergent anxiety backgrounds. We also investigated EH-induced effects at the protein and mRNA levels in adult male HAB mice in the hypothalamus, the prefrontal cortex, and the hippocampus by examining the same mitochondrial/energy pathways and mitochondrial dynamics mechanisms (fission, fusion, biogenesis, and mitophagy) in all three brain regions.EH exerts anxiolytic effects in adult HAB but not NAB male mice and does not affect HAB or NAB maternal behavior, although basal HAB vs. NAB maternal behaviors differ. In adult HAB male mice, EH does not impact oxidative phosphorylation (OXPHOS) and oxidative stress in any of the brain regions studied but leads to increased protein expression of glycolysis enzymes and a correlation of anxiety-related behavior with Krebs cycle enzymes in HAB mice in the hypothalamus. Intriguingly, EH alters mitochondrial dynamics by increasing hypothalamic DRP1, OPA1, and PGC1a protein levels. At the mRNA level, we observe altered, EH-driven mitochondrial dynamics mRNA signatures which predominantly affect the prefrontal cortex.Taken together, our results show that EH exerts anxiolytic effects in adulthood in high anxiety and modulates mitochondrial dynamics pathways in a brain region-specific manner.

Basal forebrain cholinergic systems as circuits through which traumatic stress disrupts emotional memory regulation

Contextual and spatial systems facilitate changes in emotional memory regulation brought on by traumatic stress. Cholinergic basal forebrain (chBF) neurons provide input to contextual/spatial systems and although chBF neurons are important for emotional memory, it is unknown how they contribute to the traumatic stress effects on emotional memory. Clusters of chBF neurons that project to the prefrontal cortex (PFC) modulate fear conditioned suppression and passive avoidance, while clusters of chBF neurons that project to the hippocampus (Hipp) and PFC (i.e. cholinergic medial septum and diagonal bands of Broca (chMS/DBB neurons) are critical for fear extinction. Interestingly, neither Hipp nor PFC projecting chMS/DBB neurons are critical for fear extinction. The retrosplenial cortex (RSC) is a contextual/spatial memory system that receives input from chMS/DBB neurons, but whether this chMS/DBB-RSC circuit facilitates traumatic stress effects on emotional memory remain unexplored. Traumatic stress leads to neuroinflammation and the buildup of reactive oxygen species. These two molecular processes may converge to disrupt chBF circuits enhancing the impact of traumatic stress on emotional memory.

Post-traumatic Stress Disorder: The Influence of the Environmental Context and Analysis of Oxidative Stress and Inflammatory and Glycemic Markers in Women Living in Kurdistan Regional Government-Iraq

Background Internally displaced persons (IDP) camps are still home to a large number of female survivors of the Yazidi genocide carried out in Iraq in 2014 by the Islamic organization known as the Islamic State of Iraq and Syria (ISIS). Many of these women suffer from a persistent form of post-traumatic stress disorder (PTSD), which can last for many years. On the other hand, little is known about the intricate etiology of PTSD. Objectives In this observational cross-sectional study, the biochemical parameters, including inflammatory and oxidative stress (OXS) markers, were evaluated in two groups: the case group (women with newly diagnosed PTSD) and the control group (apparently healthy women). Furthermore, how the environment impacts the biochemical and OXS parameters of people not diagnosed with PTSD but living in IDP camps was also analyzed. Materials and methods The PTSD group (n=55, age=30.0 years) was made up of women survivors of genocide-related events living in IDP camps in the Kurdistan region of Iraq. The studied parameters in the PTSD group have been compared to two healthy control groups: (1) internal control group (n=55, age=28.1 years): healthy women living inside the IDP camps; and (2) external control group (n=55, age=28.3 years): healthy women living outside the IDP camps. The diagnosis of PTSD was conducted using a validated Kurdish version of the PTSD Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5) (PCL-5) scale. Blood samples were collected to determine the level of glycated hemoglobin (HbA1c) and the concentrations of fasting serum glucose (FSG), C-reactive protein (CRP), ceruloplasmin (CP), 8-hydroxydeoxyguanosine (8-OHdG), glutathione (GSH), malondialdehyde (MDA), protein carbonyls (PC), and catalase (CAT) activity. Results Women with PTSD presented increased values of FSG (4.41%, p<0.05), HbA1c (4.74%, p<0.05), and CRP (114.29%, p<0.05), as well as increased levels of 8-OHdG (185.97%, p<0.001), CP (27.08%, p<0.001), MDA (141.97%, p<0.001), and PC (63.01%, p<0.001), besides increased CAT activity (121.5%, p<0.001), when compared with the control groups. A significant reduction of GSH (-20.33%, p<0.05) was observed in PTSD patients as compared to the external control group. In relation to the internal control group, women diagnosed with PTSD presented significantly increased levels of FSG (3.88%, p<0.05), HbA1c (2.83%, p<0.05), CRP (77.97%, p<0.05), and PC (41.3%, p<0.05), as well as increased levels of 8-OHdG (118.84%, p<0.001), CP (22.72%, p<0.001), MDA (90.67%, p<0.001), and CAT activity (55.31%, p<0.001). Healthy individuals residing in IDP camps, compared with external healthy control, presented significantly elevated levels of 8-OHdG (30.68%, p<0.001), MDA (26.91%, p<0.001), PC (15.37%, p<0.001), and CAT activity (42.62%, p<0.001). Conclusion Our findings indicate that PTSD significantly influences glycemic, inflammatory, oxidant, and antioxidant parameters, as evidenced by increased levels of FSG, HbA1C, CRP, PC, MDA, 8-OHdG, and CP, as well as increased CAT activity and a reduced GSH concentration in the PTSD group in comparison to the external control group. Additionally, our results suggest that the environmental context in IDP camps by itself can potentially affect oxidant and antioxidant parameters, as evidenced by the increased concentrations of 8-OHdG, MDA, and PC and increased CAT activity found in individuals not diagnosed with PTSD but living inside the camps.

Polyphenols in edible herbal medicine: targeting gut-brain interactions in depression-associated neuroinflammation

Supplementing with edible herbal medicine is an important strategy because of its role in nutrition. Many polyphenols, which are universal components in edible herbal medicines, have low bioavailability. Therefore, gut microbiota is a key determinant of polyphenol bioactivity. Polyphenols can alter the abundance of flora associated with neuroinflammation by reversing intestinal microbiota dysbiosis. Intestinal flora-mediated chemical modification of polyphenols can result in their conversion into active secondary metabolites. The current review summarizes the main edible medicines used in anti-depression and details the interactions between polyphenols and gut microbiota; in addition, it provides insights into the mechanisms underlying the possible suppression of neuroinflammation associated with depression, by polyphenols in edible herbal medicine. A better understanding of polyphenols with bioactivities that are crucial in edible herbal medicine may facilitate their use in the prevention and treatment of neuroinflammation associated with depression.

Diosgenin normalization of disrupted behavioral and central neurochemical activity after single prolonged stress

Introduction: Post-traumatic stress disorder (PTSD) is a chronic mental illness triggered by traumatic experiences such as wars, natural disasters, or catastrophes, and it is characterized by anxiety, depression and cognitive impairment. Diosgenin is a steroidal sapogenin with known neuroprotective and antioxidant properties. This study aimed to assess the pharmacological potential of diosgenin in a single prolonged stress (SPS) model of PTSD, plus other behavioral models along with any consequent alterations in brain neurochemistry in male mice. Methodology: SPS was induced by restraining animals for 2 h, followed by 20 min of forced swim, recuperation for 15 min, and finally, exposure to ether to induce anesthesia. The SPS-exposed animals were treated with diosgenin (20, 40, and 60 mg/kg) and compared with the positive controls, fluoxetine or donepezil, then they were observed for any changes in anxiety/depression-like behaviors, and cognitive impairment. After behavioral screening, postmortem serotonin, noradrenaline, dopamine, vitamin C, adenosine and its metabolites inosine and hypoxanthine were quantified in the frontal cortex, hippocampus, and striatum by high-performance liquid chromatography. Additionally, animal serum was screened for changes in corticosterone levels. Results: The results showed that diosgenin reversed anxiety- and depression-like behaviors, and ameliorated cognitive impairment in a dose-dependent manner. Additionally, diosgenin restored monoamine and vitamin C levels dose-dependently and modulated adenosine and its metabolites in the brain regions. Diosgenin also reinstated otherwise increased serum corticosterone levels in SPS mice. Conclusion: The findings suggest that diosgenin may be a potential candidate for improving symptoms of PTSD.

Revealing of Intracellular Antioxidants in Dendrobium nobile by High Performance Liquid Chromatography-Tandem Mass Spectrometry

The medicinal plant Dendrobium nobile is an important natural antioxidant resource. To reveal the antioxidants of D. nobile, high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was employed for metabolic analysis. The H₂O₂-induced oxidative damage was used in human embryonic kidney 293T (H293T) cells to assess intracellular antioxidant activities. Cells incubated with flower and fruit extracts showed better cell survival, lower levels of reactive oxygen species (ROS), and higher catalase and superoxide dismutase activities than those incubated with root, stem, and leaf extracts (p < 0.01). A total of 13 compounds were newly identified as intracellular antioxidants by association analysis, including coniferin, galactinol, trehalose, beta-D-lactose, trigonelline, nicotinamide-N-oxide, shikimic acid, 5'-deoxy-5'-(methylthio)adenosine, salicylic acid, isorhamnetin-3-O-neohespeidoside, methylhesperidin, 4-hydroxybenzoic acid, and cis-aconitic acid (R² > 0.8, Log₂FC > 1, distribution > 0.1%, and p < 0.01). They showed lower molecular weight and higher polarity, compared to previously identified in vitro antioxidants in D. nobile (p < 0.01). The credibility of HPLC-MS/MS relative quantification was verified by common methods. In conclusion, some saccharides and phenols with low molecular weight and high polarity helped protect H293T cells from oxidative damage by increasing the activities of intracellular antioxidant enzymes and reducing intracellular ROS levels. The results enriched the database of safe and effective intracellular antioxidants in medicinal plants.

Effects of ultrasound-induced stress on gut microbiota of mice

Background and Aim

Prolonged stress causes deleterious effects on both the organism and its microbiota. In this study, we examined the effects of exposure to variable frequency ultrasound (US) on the gut microbiota-liver-brain axis of mice.

Materials and Methods

This study was conducted on 20 mature clinically healthy sexually naive C57BL/6J male mice (42-45 days old). Group 1 (Normal) consisted of healthy intact mice (n = 10). Group 2 (Stress) consisted of mice subjected to US-induced stress (n = 10) for 20 days with alternating frequencies (20-45 kHz). Stool samples were collected on days 0, 10, and 20, and the corresponding DNA was later subjected to 16SrRNA sequencing. After mice were sacrificed on day 21, the leukocyte count, blood serum biochemical parameters, and liver and brain antioxidant status were measured. Behavioral testing was performed on days 17, 18, and 19.

Results

Ultrasound lead to higher stress and anxiety levels; increase in creatinine by 8.29% and gamma-glutamyltransferase activity by 5 times, a decrease in alkaline phosphatase activity by 38.23%, increase of de Ritis coefficient by 21.34%; increased liver and brain superoxide dismutase level by 20.8% and 21.5%, respectively; the stress-related changes in the gut microbiota composition - Bacteroidaceae and Firmicutes.

Conclusion

Subjecting mice to 20 days of US-induced stress leads to systemic disorders due to oxidative stress and a decrease in the diversity of the gut microbiota.

Cannabidiol: Bridge between Antioxidant Effect, Cellular Protection, and Cognitive and Physical Performance

The literature provides scientific evidence for the beneficial effects of cannabidiol (CBD), and these effects extend beyond epilepsy treatment (e.g., Lennox-Gastaut and Dravet syndromes), notably the influence on oxidative status, neurodegeneration, cellular protection, cognitive function, and physical performance. However, products containing CBD are not allowed to be marketed everywhere in the world, which may ultimately have a negative effect on health as a result of the uncontrolled CBD market. After the isolation of CBD follows the discovery of CB1 and CB2 receptors and the main enzymatic components (diacylglycerol lipase (DAG lipase), monoacyl glycerol lipase (MAGL), fatty acid amino hydrolase (FAAH)). At the same time, the antioxidant potential of CBD is due not only to the molecular structure but also to the fact that this compound increases the expression of the main endogenous antioxidant systems, superoxide dismutase (SOD), and glutathione peroxidase (GPx), through the nuclear complex erythroid 2-related factor (Nrf2)/Keep1. Regarding the role in the control of inflammation, this function is exercised by inhibiting (nuclear factor kappa B) NF-κB, and also the genes that encode the expression of molecules with a pro-inflammatory role (cytokines and metalloproteinases). The other effects of CBD on cognitive function and physical performance should not be excluded. In conclusion, the CBD market needs to be regulated more thoroughly, given the previously listed properties, with the mention that the safety profile is a very good one.

Leaf extract of Anacardium occidentale ameliorates biomarkers of neuroinflammation, memory loss, and neurobehavioral deficit in N(ω)-nitro-L-arginine methyl ester (L-NAME) treated rats

PURPOSE

Anacardium occidentale commonly known as Cashew is a plant that is widely used in African traditional medicine. It is endowed with phytochemical constituents that are responsible for its medicinal properties.

METHODS

Twenty-five male Wistar rats were grouped as follows: Control (Group A), Group B (L-NAME 40 mg/kg), Group C (100 mg/kg Anacardium occidentale extract plus 40 mg/kg L-NAME), Group D (200 mg/kg extract plus 40 mg/kg L-NAME) and Group E (10 mg/kg of Lisinopril plus 40 mg/kg L-NAME). The animals were treated with oral administration of either the extracts or Lisnopril daily for 4 weeks. Neuro-behavioural tests such as the Morris Water Maze and Hanging Wire Grip tests were carried out to evaluate memory/spatial learning and muscular strength, respectively. Makers of oxidative stress, antioxidant enzymes and immunohistochemical staining of Glial Fibrillary Acidic Protein and Ionised Calcium Binding Adaptor molecule 1 were assessed.

RESULTS

L-NAME administration caused significant increases in biomarkers of oxidative stress, decreased antioxidant status, acetylcholinesterase activity, altered neuro-behavioural changes, astrocytosis, and microgliosis. However, Anacardium occidentale reversed exaggerated oxidative stress biomarkers and improved neuro-behavioural changes.

CONCLUSIONS

Combining all, Anacardium occidentale enhanced brain antioxidant defence status, improved memory and muscular strength, thus, suggesting the neuroprotective properties of Anacardium occidentale.

Understanding the Role of Oxidative Stress, Neuroinflammation and Abnormal Myelination in Excessive Aggression Associated with Depression: Recent Input from Mechanistic Studies

Aggression and deficient cognitive control problems are widespread in psychiatric disorders, including major depressive disorder (MDD). These abnormalities are known to contribute significantly to the accompanying functional impairment and the global burden of disease. Progress in the development of targeted treatments of excessive aggression and accompanying symptoms has been limited, and there exists a major unmet need to develop more efficacious treatments for depressed patients. Due to the complex nature and the clinical heterogeneity of MDD and the lack of precise knowledge regarding its pathophysiology, effective management is challenging. Nonetheless, the aetiology and pathophysiology of MDD has been the subject of extensive research and there is a vast body of the latest literature that points to new mechanisms for this disorder. Here, we overview the key mechanisms, which include neuroinflammation, oxidative stress, insulin receptor signalling and abnormal myelination. We discuss the hypotheses that have been proposed to unify these processes, as many of these pathways are integrated for the neurobiology of MDD. We also describe the current translational approaches in modelling depression, including the recent advances in stress models of MDD, and emerging novel therapies, including novel approaches to management of excessive aggression, such as anti-diabetic drugs, antioxidant treatment and herbal compositions.

Aberrant Ganglioside Functions to Underpin Dysregulated Myelination, Insulin Signalling, and Cytokine Expression: Is There a Link and a Room for Therapy?

Gangliosides are molecules widely present in the plasma membranes of mammalian cells, participating in a variety of processes, including protein organization, transmembrane signalling and cell adhesion. Gangliosides are abundant in the grey matter of the brain, where they are critically involved in postnatal neural development and function. The common precursor of the majority of brain gangliosides, GM3, is formed by the sialylation of lactosylceramide, and four derivatives of its a- and b-series, GM1, GD1a, GD1b and GT1b, constitute 95% of all the brain gangliosides. Impairments in ganglioside metabolism due to genetic abnormalities of GM-synthases are associated with severe neurological disorders. Apart from that, the latest genome-wide association and translational studies suggest a role of genes involved in brain ganglioside synthesis in less pervasive psychiatric disorders. Remarkably, the most recent animal studies showed that abnormal ganglioside functions result in dysregulated neuroinflammation, aberrant myelination and altered insulin receptor signalling. At the same time, these molecular features are well established as accompanying developmental psychiatric disorders such as attention-deficit hyperactivity disorder (ADHD) and autism spectrum disorders (ASD). This led us to hypothesize a role of deficient ganglioside function in developmental neuropsychiatric disorders and warrants further gene association clinical studies addressing this question. Here, we critically review the literature to discuss this hypothesis and focus on the recent studies on ST3GAL5-deficient mice. In addition, we elaborate on the therapeutic potential of various anti-inflammatory remedies for treatment of developmental neuropsychiatric conditions related to aberrant ganglioside functions.

Immunomodulatory effects of new phytotherapy on human macrophages and TLR4- and TLR7/8-mediated viral-like inflammation in mice

Background

While all efforts have been undertaken to propagate the vaccination and develop remedies against SARS-CoV-2, no satisfactory management of this infection is available yet. Moreover, poor availability of any preventive and treatment measures of SARS-CoV-2 in economically disadvantageous communities aggravates the course of the pandemic. Here, we studied a new immunomodulatory phytotherapy (IP), an extract of blackberry, chamomile, garlic, cloves, and elderberry as a potential low-cost solution for these problems given the reported efficacy of herbal medicine during the previous SARS virus outbreak.

Methods

The key feature of SARS-CoV-2 infection, excessive inflammation, was studied in in vitro and in vivo assays under the application of the IP. First, changes in tumor-necrosis factor (TNF) and lnteurleukin-1 beta (IL-1β) concentrations were measured in a culture of human macrophages following the lipopolysaccharide (LPS) challenge and treatment with IP or prednisolone. Second, chronically IP-pre-treated CD-1 mice received an agonist of Toll-like receptors (TLR)-7/8 resiquimod and were examined for lung and spleen expression of pro-inflammatory cytokines and blood formula. Finally, chronically IP-pre-treated mice challenged with LPS injection were studied for “sickness” behavior. Additionally, the IP was analyzed using high-potency-liquid chromatography (HPLC)-high-resolution-mass-spectrometry (HRMS).

Results

LPS-induced in vitro release of TNF and IL-1β was reduced by both treatments. The IP-treated mice displayed blunted over-expression of SAA-2, ACE-2, CXCL1, and CXCL10 and decreased changes in blood formula in response to an injection with resiquimod. The IP-treated mice injected with LPS showed normalized locomotion, anxiety, and exploration behaviors but not abnormal forced swimming. Isoquercitrin, choline, leucine, chlorogenic acid, and other constituents were identified by HPLC-HRMS and likely underlie the IP immunomodulatory effects.

Conclusions

Herbal IP-therapy decreases inflammation and, partly, “sickness behavior,” suggesting its potency to combat SARS-CoV-2 infection first of all via its preventive effects.

Tenofovir-silver nanoparticles conjugate ameliorates neurocognitive disorders and protects ultrastructural and cytoarchitectonic properties of the prefrontal cortex in diabetic rats

Tenofovir disoproxil fumarate (TDF) is the highly recommended antiretroviral drug in human immunodeficiency virus management. Although research has shown the neurological and metabolic disorders associated with TDF administration, the effect of TDF-silver nanoparticles conjugate (TDF-AgNPs) on the disorders has not been fully elucidated. Thus, this study evaluated the neuroprotective effects of TDF-AgNPs on ultrastructural and cytoarchitectonic properties of the prefrontal cortex (PFC) in diabetic rats. Forty-two adult male Sprague-Dawley rats (250 ± 13 g) were randomly divided into non-diabetic groups (1-3) and diabetic groups (4-6), each administered distilled water (0.5 ml/100g, p.o), TDF (26.8 mg/kg/bw, p.o) or TDF-AgNPs (6.7 mg/kg, i.p). After eight weeks of administration, cognitive function, oxidative injury and tissue inflammation were evaluated. Also, PFC ultrastructure was observed using transmission electron microscopy, Nissl staining and immunohistochemistry. Diabetic rats administered TDF exhibited cognitive deficits; and increases in blood glucose, malondialdehyde and interleukin-1 beta (IL-1β) levels, which correlate with decreases in glutathione level, and superoxide dismutase (SOD) and catalase activities. Furthermore, loss of PFC astrocytes and neuronal organelles was observed. Conversely, TDF-AgNPs administration to diabetic rats improved cognitive deficits; and increased glutathione, SOD, and catalase, but reduced PFC malondialdehyde and IL-1β concentrations. Notably, TDF-AgNPs prevented loss of PFC neurons and astrocytic cells, and morphology aberration of neuronal organelles. This study suggests that TDF-AgNPs attenuated cognitive deficits via silver nanoparticles' antioxidant and anti-inflammatory properties, preventing the loss of PFC astrocytes and neurons. The TDF-AgNPs may be utilized to ameliorate the neurological dysfunction caused by prolonged TDF administration.

Who Benefits from Fermented Food Consumption? A Comparative Analysis between Psychiatrically Ill and Psychiatrically Healthy Medical Students

Probiotic therapies and fermented food diets hold promise for improving mental health. Although in this regard psychiatric patients appear to benefit more than healthy individuals, no research has been performed to directly evaluate this hypothesis. The present study examined a cohort of medical students facing a stressful event, and some of the students reported suffering from chronic psychiatric diseases. The amount of fermented food consumption was calculated with the use of seven-day dietary records, while depressive and anxiety symptoms were assessed with the use of the Patient Health Questionnaire-9 and Generalized Anxiety Disorder-7, respectively. In psychiatrically healthy medical students under psychological stress (n = 372), higher fermented food consumption was associated with more depressive and anxiety symptoms. In contrast, psychiatrically ill medical students (n = 25, 6.3% of all the participants) were found to present a negative association between the amount of fermented food consumed and the severity of depressive symptoms (adjusted β −0.52, 95% CI −0.85 to −0.19, p = 0.0042); however, this relationship was insignificant for anxiety symptoms (adjusted β −0.22, 95% CI −0.59 to 0.15, p = 0.22). A significant interaction was found between the consumption of fermented food and psychiatric diagnosis in predicting depressive symptoms (p = 0.0001), and a borderline significant interaction for anxiety symptoms (p = 0.053). In conclusion, psychiatrically ill people, but not healthy ones, may benefit from fermented food consumption in terms of alleviation of depressive symptoms. Our findings require cautious interpretation and further investigation.

Predation Stress Causes Excessive Aggression in Female Mice with Partial Genetic Inactivation of Tryptophan Hydroxylase-2: Evidence for Altered Myelination-Related Processes

The interaction between brain serotonin (5-HT) deficiency and environmental adversity may predispose females to excessive aggression. Specifically, complete inactivation of the gene encoding tryptophan hydroxylase-2 (Tph2) results in the absence of neuronal 5-HT synthesis and excessive aggressiveness in both male and female null mutant (Tph2−/−) mice. In heterozygous male mice (Tph2+/−), there is a moderate reduction in brain 5-HT levels, and when they are exposed to stress, they exhibit increased aggression. Here, we exposed female Tph2+/− mice to a five-day rat predation stress paradigm and assessed their emotionality and social interaction/aggression-like behaviors. Tph2+/− females exhibited excessive aggression and increased dominant behavior. Stressed mutants displayed altered gene expression of the 5-HT receptors Htr1a and Htr2a, glycogen synthase kinase-3 β (GSK-3β), and c-fos as well as myelination-related transcripts in the prefrontal cortex: myelin basic protein (Mbp), proteolipid protein 1 (Plp1), myelin-associated glycoprotein (Mag), and myelin oligodendrocyte glycoprotein (Mog). The expression of the plasticity markers synaptophysin (Syp) and cAMP response element binding protein (Creb), but not AMPA receptor subunit A2 (GluA2), were affected by genotype. Moreover, in a separate experiment, naïve female Tph2+/− mice showed signs of enhanced stress resilience in the modified swim test with repeated swimming sessions. Taken together, the combination of a moderate reduction in brain 5-HT with environmental challenges results in behavioral changes in female mice that resemble the aggression-related behavior and resilience seen in stressed male mutants; additionally, the combination is comparable to the phenotype of null mutants lacking neuronal 5-HT. Changes in myelination-associated processes are suspected to underpin the molecular mechanisms leading to aggressive behavior.

Importance of gut microbiome regulation for the prevention and recovery process after SARS‑CoV‑2 respiratory viral infection (Review)

Infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been reported to affect organs other than the lungs, including the liver, brain, kidneys and intestine, and gastrointestinal symptoms, such as nausea, vomiting, diarrhea and abdominal discomfort, have also been reported. Thus, SARS-CoV-2 could potentially directly or indirectly regulate the gut microbiome profile and its homeostasis. The abundance of Coprobacillus, Clostridium ramosum and Clostridium are associated with the severity of COVID-19, and Firmicutes, Bacteriodetes, Proteobacteria and Actinobacteria are also related to COVID-19 infection. The four phyla are correlated with the severity of COVID-19 infection in patients. The modulation of factors that control the physiological growth of the gut microbiome will determine the proportionate ratio of microbiome types (profile). Taken together, gut microbiome profile alterations in COVID-19 patients may have a cross effect with the modulation of cytokine levels in COVID-19 infection. With these findings, several factors that regulate gut microbiome homeostasis may support the degree of the clinical symptoms and hasten the recovery process after COVID-19 infection.

Hippocampal Over-Expression of Cyclooxygenase-2 (COX-2) Is Associated with Susceptibility to Stress-Induced Anhedonia in Mice

The phenomenon of individual variability in susceptibility/resilience to stress and depression, in which the hippocampus plays a pivotal role, is attracting increasing attention. We investigated the potential role of hippocampal cyclooxygenase-2 (COX-2), which regulates plasticity, neuroimmune function, and stress responses that are all linked to this risk dichotomy. We used a four-week-long chronic mild stress (CMS) paradigm, in which mice could be stratified according to their susceptibility/resilience to anhedonia, a key feature of depression, to investigate hippocampal expression of COX-2, a marker of microglial activation Iba-1, and the proliferation marker Ki67. Rat exposure, social defeat, restraints, and tail suspension were used as stressors. We compared the effects of treatment with either the selective COX-2 inhibitor celecoxib (30 mg/kg/day) or citalopram (15 mg/kg/day). For the celecoxib and vehicle-treated mice, the Porsolt test was used. Anhedonic (susceptible) but not non-anhedonic (resilient) animals exhibited elevated COX-2 mRNA levels, increased numbers of COX-2 and Iba-1-positive cells in the dentate gyrus and the CA1 area, and decreased numbers of Ki67-positive cells in the subgranular zone of the hippocampus. Drug treatment decreased the percentage of anhedonic mice, normalized swimming activity, reduced behavioral despair, and improved conditioned fear memory. Hippocampal over-expression of COX-2 is associated with susceptibility to stress-induced anhedonia, and its pharmacological inhibition with celecoxib has antidepressant effects that are similar in size to those of citalopram.