Shedding light on biological sex differences and microbiota-gut-brain axis: a comprehensive review of its roles in neuropsychiatric disorders

Identification of dietary factors that impact the gut microbiota associated with vitiligo: A Mendelian randomization study and meta-analysis

Previous observational studies have suggested that gut microbiota might be associated with vitiligo. However, owing to the limitations in observational studies of reverse causality and confounders, it remains unclear that whether and how the causal relationships exist. The results suggested that pylum.Bacteroidetes, family.BacteroidalesS24.7, genus.LachnospiraceaeND3007, genus.Marvinbryantia are protective factors for vitiligo. Conversely, family.Lachnospiraceae, order.Burkholderiales, genus.Adlercreutzia, genus.Catenibacterium and genus.Lachnospira are risk factors for vitiligo. In addition, the causative connection between dietary factors and the gut microbiota associated with vitiligo was also investigated. The results revealed that 'alcohol intake versus 10 years pervious' results in a reduction in the abundance of genus.Lachnospiraceae ND3007 and family.BacteroidalesS24.7, bread intake leads to a reduction of genus.Marvinbryantia, 'average weekly red wine intake' is linked to a decrease in the abundance of order.Burkholderiales, tea intake is associated with an augmentation in the abundance of genus.Catenibacterium, salad/raw vegetable intake elevates the abundance of order.Burkholderiales. In summary, this Mendelian randomization study substantiates potential causal effects of gut microbiota on vitiligo. Modulating the gut microbiota through regulating dietary composition may be a novel strategy for preventing vitiligo.

Early Life Stress and Major Depressive Disorder-An Update on Molecular Mechanisms and Synaptic Impairments

Early life stress (ELS), characterized as abuse, neglect, and abandonment, can cause several adverse consequences in the lives of affected individuals. ELS experiences can affect an individual's development in variable ways, persisting in the long term and promoting lasting impacts, considering that early exposure to stressors can be biologically incorporated, as prolonged stimulation of stress response systems affects the development of the brain structure and other body systems, increasing the risk of diseases associated with stress and cognitive impairment. This type of stress increases the risk of developing major depressive disorder (MDD) in a severe form that does not respond adequately to traditional antidepressant treatments. Several alterations are studied as mechanisms that relate ELS with MDD, such as epigenetic alterations, neurotransmitters, and neuronal signaling. This review discusses research that brings evidence about the ELS mechanisms involved in synaptic impairments and MDD. The processes involved in epigenetic changes and the HPA axis are highlighted, as well as changes in neurotransmitters and neuronal signaling mechanisms.

Deciphering the microbial map and its implications in the therapeutics of neurodegenerative disorder

Every facet of biological anthropology, including development, ageing, diseases, and even health maintenance, is influenced by gut microbiota's significant genetic and metabolic capabilities. With current advancements in sequencing technology and with new culture-independent approaches, researchers can surpass older correlative studies and develop mechanism-based studies on microbiome-host interactions. The microbiota-gut-brain axis (MGBA) regulates glial functioning, making it a possible target for the improvement of development and advancement of treatments for neurodegenerative diseases (NDDs). The gut-brain axis (GBA) is accountable for the reciprocal communication between the gastrointestinal and central nervous system, which plays an essential role in the regulation of physiological processes like controlling hunger, metabolism, and various gastrointestinal functions. Lately, studies have discovered the function of the gut microbiome for brain health-different microbiota through different pathways such as immunological, neurological and metabolic pathways. Additionally, we review the involvement of the neurotransmitters and the gut hormones related to gut microbiota. We also explore the MGBA in neurodegenerative disorders by focusing on metabolites. Further, targeting the blood-brain barrier (BBB), intestinal barrier, meninges, and peripheral immune system is investigated. Lastly, we discuss the therapeutics approach and evaluate the pre-clinical and clinical trial data regarding using prebiotics, probiotics, paraprobiotics, fecal microbiota transplantation, personalised medicine, and natural food bioactive in NDDs. A comprehensive study of the GBA will felicitate the creation of efficient therapeutic approaches for treating different NDDs.

Sex differences in opioid response: a role for the gut microbiome?

Opioid drugs have been long known to induce different responses in males compared to females, however, the molecular mechanisms underlying these effects are yet to be fully characterized. Recent studies have established a link between the gut microbiome and behavioral responses to opioids. Chronic opioid use is associated with gut dysbiosis, or microbiome disruptions, which is thought to contribute to altered opioid analgesia and reward processing. Gut microbiome composition and functioning have also been demonstrated to be influenced by sex hormones. Despite this, there is currently very little work investigating whether sex differences in the gut microbiome mediate sex-dependent responses to opioids, highlighting a critical gap in the literature. Here, we briefly review the supporting evidence implicating a potential role for the gut microbiome in regulating sexually dimorphic opioid response and identify areas for future research.

Brain-body mechanisms contribute to sexual dimorphism in amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis (ALS) is the most common form of human motor neuron disease. It is characterized by the progressive degeneration of upper and lower motor neurons, leading to generalized motor weakness and, ultimately, respiratory paralysis and death within 3-5 years. The disease is shaped by genetics, age, sex and environmental stressors, but no cure or routine biomarkers exist for the disease. Male individuals have a higher propensity to develop ALS, and a different manifestation of the disease phenotype, than female individuals. However, the mechanisms underlying these sex differences remain a mystery. In this Review, we summarize the epidemiology of ALS, examine the sexually dimorphic presentation of the disease and highlight the genetic variants and molecular pathways that might contribute to sex differences in humans and animal models of ALS. We advance the idea that sexual dimorphism in ALS arises from the interactions between the CNS and peripheral organs, involving vascular, metabolic, endocrine, musculoskeletal and immune systems, which are strikingly different between male and female individuals. Finally, we review the response to treatments in ALS and discuss the potential to implement future personalized therapeutic strategies for the disease.

Neurological Disorders Induced by Drug Use: Effects of Adolescent and Embryonic Drug Exposure on Behavioral Neurodevelopment

Clinical studies demonstrate that the risk of developing neurological disorders is increased by overconsumption of the commonly used drugs, alcohol, nicotine and cannabis. These drug-induced neurological disorders, which include substance use disorder (SUD) and its co-occurring emotional conditions such as anxiety and depression, are observed not only in adults but also with drug use during adolescence and after prenatal exposure to these drugs, and they are accompanied by long-lasting disturbances in brain development. This report provides overviews of clinical and preclinical studies, which confirm these adverse effects in adolescents and the offspring prenatally exposed to the drugs and include a more in-depth description of specific neuronal systems, their neurocircuitry and molecular mechanisms, affected by drug exposure and of specific techniques used to determine if these effects in the brain are causally related to the behavioral disturbances. With analysis of further studies, this review then addresses four specific questions that are important for fully understanding the impact that drug use in young individuals can have on future pregnancies and their offspring. Evidence demonstrates that the adverse effects on their brain and behavior can occur: (1) at low doses with short periods of drug exposure during pregnancy; (2) after pre-conception drug use by both females and males; (3) in subsequent generations following the initial drug exposure; and (4) in a sex-dependent manner, with drug use producing a greater risk in females than males of developing SUDs with emotional conditions and female offspring after prenatal drug exposure responding more adversely than male offspring. With the recent rise in drug use by adolescents and pregnant women that has occurred in association with the legalization of cannabis and increased availability of vaping tools, these conclusions from the clinical and preclinical literature are particularly alarming and underscore the urgent need to educate young women and men about the possible harmful effects of early drug use and to seek novel therapeutic strategies that might help to limit drug use in young individuals.

Gender-specific insights into the irritable bowel syndrome pathophysiology. Focus on gut dysbiosis and permeability

Irritable bowel syndrome (IBS) is the most common functional gastrointestinal disorder involving the brain-gut interaction. IBS is characterized by persistent abdominal pain and changes in bowel habits. IBS exerts significant impacts on quality of life and imposes huge economic costs. Global epidemiological data reveal variations in IBS prevalence, both globally and between genders, necessitating comprehensive studies to uncover potential societal and cultural influences. While the exact pathophysiology of IBS remains incompletely understood, the mechanism involves a dysregulation of the brain-gut axis, leading to disturbed intestinal motility, local inflammation, altered intestinal permeability, visceral sensitivity, and gut microbiota composition. We reviewed several gender-related pathophysiological aspects of IBS pathophysiology, by focusing on gut dysbiosis and intestinal permeability. This perspective paves the way to personalized and multidimensional clinical management of individuals with IBS.

COVID-19 and Youth Mental Health Disparities: Intersectional Trends in Depression, Anxiety and Suicide Risk-Related Diagnoses

OBJECTIVES

Mental health disparities were prevalent among racially and ethnically minoritized youth prior to the COVID-19 pandemic. As complete datasets from 2022 become available, we can estimate the extent to which the pandemic further magnified existing inequities. Our objective was to quantify disparities in trajectories of depression, anxiety, and suicide risk-related diagnoses in youth before and after the start of the COVID-19 pandemic, using an intersectional lens of race, ethnicity and gender.

METHODS

Using electronic medical record data from one mid-Atlantic health care system (2015-2022), we evaluated changes in annual rates of depression, anxiety and suicide risk-related diagnoses in 29,117 youths, aged 8-20 years, using graphical analysis, comparison of adjusted mean differences (AMD) and adjusted mixed multilevel logistic regression.

RESULTS

Almost all racial and gender subgroups had significantly higher rates of depression and anxiety after the start of COVID-19 compared to the years prior, with the greatest changes observed in Hispanic and Asian females. Suicide risk-related diagnoses significantly increased among all female subgroups, with the largest increase among Asian females (AMD 4.8, 95% CI 0.2-9.3) and Black females (AMD 4.6, 95% CI 2.2-6.9).

CONCLUSIONS

Rates of depression, anxiety, and suicidal thoughts and/or behaviors in young people continued to increase in the post-pandemic period. Many pre-existing disparities between subgroups, especially females, significantly widened, highlighting the importance of using an intersectional lens. Urgent action is warranted, including universal screening of pediatric patients for suicide risk, broadening effective treatment and support options in minoritized patients, and increasing support services to patients and families.

Electroacupuncture intervention alleviates depressive-like behaviors and regulates gut microbiome in a mouse model of depression

Electroacupuncture (EA) is a neuroregulatory therapy for depression. Nonetheless, the effects of EA on the gut microbiome in mice models of depression are not well established. Here, using a chronic unpredictable mild stress (CUMS) model in mice, we evaluated the antidepressant effects of EA and changes in gut microbiota with behavioral tests and 16S rRNA gene sequencing. The results found that EA increased the time spent in the center area of the open-field test and the percentage of sucrose preference and reduced the immobility time in the tail suspension test in CUMS-treated mice. Furthermore, the genus Lachnoclostridium, Ruminococcaceae_UCG-002 and Rikenellaceae_RC9_gut_group were enriched in the CUMS group, which was positively correlated with depressive-like behaviors. Whereas phylum Actinobacteria and genus Allobaculum, Bifidobacterium, Dubosiella, Rikenella and Ileibacterium were enriched in the EA and CUMS + EA groups, all of which were negatively correlated with depressive-like behaviors. This study characterizes gut microbiota under EA treatment and provides new insights into the association of anti-depressive-like effects of EA and gut microbiota.

Gut-Brain Axis: Focus on Sex Differences in Neuroinflammation

In recent years, there has been a growing interest in the concept of the "gut-brain axis". In addition to well-studied diseases associated with an imbalance in gut microbiota, such as cancer, chronic inflammation, and cardiovascular diseases, research is now exploring the potential role of gut microbial dysbiosis in the onset and development of brain-related diseases. When the function of the intestinal barrier is altered by dysbiosis, the aberrant immune system response interacts with the nervous system, leading to a state of "neuroinflammation". The gut microbiota-brain axis is mediated by inflammatory and immunological mechanisms, neurotransmitters, and neuroendocrine pathways. This narrative review aims to illustrate the molecular basis of neuroinflammation and elaborate on the concept of the gut-brain axis by virtue of analyzing the various metabolites produced by the gut microbiome and how they might impact the nervous system. Additionally, the current review will highlight how sex influences these molecular mechanisms. In fact, sex hormones impact the brain-gut microbiota axis at different levels, such as the central nervous system, the enteric nervous one, and enteroendocrine cells. A deeper understanding of the gut-brain axis in human health and disease is crucial to guide diagnoses, treatments, and preventive interventions.

Dysregulated brain-gut axis in the setting of traumatic brain injury: review of mechanisms and anti-inflammatory pharmacotherapies

Traumatic brain injury (TBI) is a chronic and debilitating disease, associated with a high risk of psychiatric and neurodegenerative diseases. Despite significant advancements in improving outcomes, the lack of effective treatments underscore the urgent need for innovative therapeutic strategies. The brain-gut axis has emerged as a crucial bidirectional pathway connecting the brain and the gastrointestinal (GI) system through an intricate network of neuronal, hormonal, and immunological pathways. Four main pathways are primarily implicated in this crosstalk, including the systemic immune system, autonomic and enteric nervous systems, neuroendocrine system, and microbiome. TBI induces profound changes in the gut, initiating an unrestrained vicious cycle that exacerbates brain injury through the brain-gut axis. Alterations in the gut include mucosal damage associated with the malabsorption of nutrients/electrolytes, disintegration of the intestinal barrier, increased infiltration of systemic immune cells, dysmotility, dysbiosis, enteroendocrine cell (EEC) dysfunction and disruption in the enteric nervous system (ENS) and autonomic nervous system (ANS). Collectively, these changes further contribute to brain neuroinflammation and neurodegeneration via the gut-brain axis. In this review article, we elucidate the roles of various anti-inflammatory pharmacotherapies capable of attenuating the dysregulated inflammatory response along the brain-gut axis in TBI. These agents include hormones such as serotonin, ghrelin, and progesterone, ANS regulators such as beta-blockers, lipid-lowering drugs like statins, and intestinal flora modulators such as probiotics and antibiotics. They attenuate neuroinflammation by targeting distinct inflammatory pathways in both the brain and the gut post-TBI. These therapeutic agents exhibit promising potential in mitigating inflammation along the brain-gut axis and enhancing neurocognitive outcomes for TBI patients.

Do microbes play a role in Alzheimer's disease?

Alzheimer's disease is a complex and progressive condition that affects essential neurological functions such as memory and reasoning. In the brain, neuronal loss, synaptic dysfunction, proteinopathy, neurofibrillary tangles, and neuroinflammation are the hallmarks of Alzheimer's disease pathophysiology. In addition, recent evidence has highlighted that microbes, whether commensal or pathogenic, also have the ability to interact with their host and to regulate its immune system, therefore participating in the exchanges that lead to peripheral inflammation and neuropathology. Because of this intimate relationship, bacteria, viruses, fungi, and protozoa have been implicated in the development of Alzheimer's disease. Here, we bring together current and most recent evidence of the role of microbes in Alzheimer's disease, raising burning questions that need to be addressed to guide therapeutic approaches and potential prophylactic strategies.

Gender-affirming hormone therapy preserves skeletal maturation in young mice via the gut microbiome

Gender-affirming hormone therapy (GAHT) is often prescribed to transgender (TG) adolescents to alleviate gender dysphoria, but the effect of GAHT on the growing skeleton is unclear. We found GAHT to improve trabecular bone structure via increased bone formation in young male mice and not to affect trabecular structure in female mice. GAHT modified gut microbiome composition in both male and female mice. However, fecal microbiota transfers (FMTs) revealed that GAHT-shaped gut microbiome was a communicable regulator of bone structure and turnover in male, but not in female mice. Mediation analysis identified 2 species of Bacteroides as significant contributors to the skeletal effects of GAHT in male mice, with Bacteroides supplementation phenocopying the effects of GAHT on bone. Bacteroides have the capacity to expand Treg populations in the gut. Accordingly, GAHT expanded intestinal Tregs and stimulated their migration to the bone marrow (BM) in male but not in female mice. Attesting to the functional relevance of Tregs, pharmacological blockade of Treg expansion prevented GAHT-induced bone anabolism. In summary, in male mice GAHT stimulated bone formation and improved trabecular structure by promoting Treg expansion via a microbiome-mediated effect, while in female mice, GAHT neither improved nor impaired trabecular structure.

A developmental framework for understanding the influence of sex and gender on health: Pediatric pain as an exemplar

Sex differences are a robust finding in many areas of adult health, including cardiovascular disease, psychiatric disorders, and chronic pain. However, many sex differences are not consistently observed until after the onset of puberty. This has led to the hypothesis that hormones are primary contributors to sex differences in health outcomes, largely ignoring the relative contributions of early developmental influences, emerging psychosocial factors, gender, and the interaction between these variables. In this paper, we argue that a comprehensive understanding of sex and gender contributions to health outcomes should start as early as conception and take an iterative biopsychosocial-developmental perspective that considers intersecting social positions. We present a conceptual framework, informed by a review of the literature in basic, clinical, and social science that captures how critical developmental stages for both sex and gender can affect children's health and longer-term outcomes. The literature on pediatric chronic pain is used as a worked example of how the framework can be applied to understanding different chronic conditions.

The gut microbiome modulates the susceptibility to traumatic stress in a sex-dependent manner

Post-traumatic stress disorder (PTSD), a psychological condition triggered by exposure to extreme or chronic stressful events, exhibits a sex bias in incidence and clinical manifestations. Emerging research implicates the gut microbiome in the pathogenesis of PTSD and its roles in stress susceptibility. However, it is unclear whether differential gut microbiota contribute to PTSD susceptibility in male and female rats. Here, we utilized the single prolonged stress animal model and employed unsupervised machine learning to classify stressed animals into stress-susceptible subgroups and stress-resilient subgroups. Subsequently, using 16S V3-V4 rDNA sequencing, we investigated the differential gut microbiota alterations between susceptible and resilient individuals in male and female rats. Our findings revealed distinct changes in gut microbiota composition between the sexes at different taxonomic levels. Furthermore, the abundance of Parabacteroides was lower in rats that underwent SPS modeling compared to the control group. In addition, the abundance of Tenericutes in the stress-susceptible subgroup was higher than that in the control group and stress-resilient subgroup, suggesting that Tenericutes may be able to characterize stress susceptibility. What is particularly interesting here is that Cyanobacteria may be particularly associated with anti-anxiety effects in male rats. This study underscores sex-specific variations in gut microbiota composition in response to stress and sex differences should be taken into account when using macrobiotics for neuropsychiatric treatment, highlighting potential targets for PTSD therapeutic interventions.

Trends in the disease burden of anxiety disorders in middle-aged and older adults in China

BACKGROUND

Anxiety disorders in middle-aged and older adults are an important public health concern in China. Based on the data in the global disease burden (GDB) research database, this study evaluated and analyzed the trend of the disease burden of middle-aged and older patients living with anxiety in China in the past 30 years.

METHODS

The incidence and disability-adjusted life years (DALYs) data of anxiety disorders in China for individuals aged 45-89 years were collected from the Global Burden of Disease Study 2019, and the effects of age, period, and cohort on the incidence of and DALY rate for anxiety disorders were analysed using an age-period-cohort model. Because of the COVID-19 pandemic, the global disease burden research database has not been updated since 2019. However, this did not affect the analysis of future trends in this study, which combined data in the past three decades from 1990 to 2019.

RESULTS

(1) The overall age-standardised incidence rate (ASIR) and age-standardised DALY rate (ASDR) for anxiety disorders in middle-aged and older adults in China decreased by 4.0 and 7.7% from 1990 to 2019, respectively, and the ASIR and ASDR were always higher in women than in men. (2)Age-period-cohort analysis showed that the net drifts for incidence and DALY rate were - 0.27% and - 0.55% per year, respectively. For both genders, the local drifts for incidence were lower than zero in those aged 45-79 years and higher than zero in those aged 80-89 years; the local drifts for the DALY rate were lower than zero in all groups. (3) From the 1990-1994 to 2015-2019, the relative risks of anxiety disorder incidence and DALY decreased by 5.6 and 7.3% in men and 4.3 and 11.7% in women, respectively.

CONCLUSION

The disease burden of anxiety disorders in middle-aged and older adults in China has been relieved over the past 30 years; however, recent ASDR, ASDR, period, and cohort effects have shown adverse trends. The incidence and DALY rate decreased with age in women, while men showed a trend of increasing first and decreasing afterwards.

Exploring gender differences in the relationship between gut microbiome and depression - a scoping review

Background

Major depressive disorder (MDD) exhibits gender disparities, and emerging evidence suggests the involvement of the gut microbiome, necessitating exploration of sex-specific differences.

Methods

A review was conducted, encompassing a thorough examination of relevant studies available in Medline via Ovid, Embase via OvidSP, CINAHL, and PsycINFO databases from their inception to June 2023. The search strategy employed specific keywords and Medical Subject Headings (MeSH) terms tailored to major depressive disorder in women, encompassing unipolar depression, depressive symptoms, and dysbiosis.

Results

Five studies were included. Among the four studies, alterations in alpha (n=1) and beta diversity (n=3) in the gut microbiome of individuals with MDD were revealed compared to controls. Gender-specific differences were observed in four studies, demonstrating the abundance of specific bacterial taxa and highlighting potential sex-specific implications in MDD pathophysiology. Correlation analyses (n=4) indicated associations between certain bacterial taxa and the severity of depressive symptoms, with varying patterns between males and females. Studies (n=3) also highlighted promising findings regarding the potential utility of microbial markers in diagnosing MDD, emphasizing the crucial role of sex stratification in understanding the disease pathophysiology.

Conclusions

The findings underscore the importance of recognizing gender-specific differences in the composition of the gut microbiome and its relationship with MDD. Further comprehensive robust studies are required to unravel the intricate mechanisms underlying these disparities.

The association between energy-adjusted dietary inflammatory index and physical activity with sleep quality: a cross-sectional study

BACKGROUND

The study aimed to assess the independent and interactive association of energy-adjusted dietary inflammatory index (E-DII) and physical activity (PA) with sleep quality.

METHOD

A cross-sectional study was conducted on the 2466 participants (60% women). A 116-item food frequency questionnaire (FFQ) was applied to calculate E-DII, the International Physical Activity Questionnaire (IPAQ) long form for PA, and the Pittsburgh sleep quality index (PSQI) to assess sleep quality were collected via interview. Multivariate logistic regression was applied to assess independent and interactive associations of E-DII and PA with sleep quality.

RESULT

No significant association was observed between E-DII and sleep quality (OR: 0.96, 95% CI: 0.92_1.01). Also, there was no significant association between the levels of PA and sleep quality. Women had 70% increased odds for poor sleep quality (OR: 1.7, 95% CI: 1.39_2.09) compared with men. No interactive association was observed between E-DII and PA levels with sleep quality.

CONCLUSION

No significant association was observed between E-DII and PA levels with sleep quality. The study indicates a gender difference in sleep quality. Future prospective studies are required to confirm these findings.

Racial and Gender Disparities in Suicide and Mental Health Care Utilization in a Pediatric Primary Care Setting

PURPOSE

We examined racial and gender disparities in the underrecognition of mental health disorders in adolescents and young adults as defined by a suicide-related diagnosis without a previous mental or behavioral health diagnosis.

METHODS

We employed a series of adjusted mixed multilevel logistic regression models to determine the odds of specific mental health diagnoses (anxiety, depression, and suicide-related) in a large, U.S. pediatric ambulatory care group (ages 8-20 years) using Electronic Medical Record Data.

RESULTS

Using the reference group of White males, White females had 17% increased odds of having a suicide-related diagnosis (odds ratio (OR) 1.17, 95% confidence intervals (CI) 1.03, 1.34) and Black females had 48% increased odds of suicide-related diagnosis (OR 1.48, 95% CI 1.28, 1.71). Conversely, White females had 75% increased odds of recorded anxiety (OR 1.75, 95% CI 1.62, 1.89), Black males had 62% decreased odds of anxiety (OR 0.38, 95% CI 0.33, 0.42), and Black females had 33% decreased odds of anxiety (OR 0.67, 95% CI 0.60, 0.74). White females had 81% increased odds of having recorded depression (OR 1.81, 95% CI 1.62, 2.04) and Black females had 80% increased odds of underrecognized need for mental or behavioral health diagnosis services (OR 1.80, 95% CI 1.53, 2.13) as defined by a suicide-related diagnosis without a previous mental health diagnosis.

DISCUSSION

Black adolescents and young adult patients are either not accessing or identified as needing mental health services at the same rates as their White peers, and Black females are experiencing the most underrecognition of need for mental health services.

Microbiome Depletion Increases Fentanyl Self-Administration and Alters the Striatal Proteome Through Short-Chain Fatty Acids

Opioid use disorder (OUD) is a public health crisis currently being exacerbated by increased rates of use and overdose of synthetic opioids, primarily fentanyl. Therefore, the identification of novel biomarkers and treatment strategies to reduce problematic fentanyl use and relapse to fentanyl taking is critical. In recent years, there has been a growing body of work demonstrating that the gut microbiome can serve as a potent modulator of the behavioral and transcriptional responses to both stimulants and opioids. Here, we advance this work to define how manipulations of the microbiome drive fentanyl intake and fentanyl-seeking in a translationally relevant drug self-administration model. Depletion of the microbiome of male rats with broad spectrum antibiotics leads to increased drug administration on increased fixed ratio, progressive ratio, and drug seeking after abstinence. Utilizing 16S  sequencing of microbiome contents from these animals, specific populations of bacteria from the gut microbiome correlate closely with levels of drug taking. Additionally, global proteomic analysis of the nucleus accumbens following microbiome manipulation and fentanyl administration to define how microbiome status alters the functional proteomic landscape in this key limbic substructure. These data demonstrate that an altered microbiome leads to marked changes in the synaptic proteome in response to repeated fentanyl treatment. Finally, behavioral effects of microbiome depletion are reversible by upplementation of the microbiome derived short-chain fatty acid metabolites. Taken together, these findings establish clear relevance for gut-brain signaling in models of OUD and lay foundations for further translational work in this space.

The Effect of Cross-Sex Fecal Microbiota Transplantation on Metabolism and Hormonal Status in Adult Rats

Increasing evidence of sexual dimorphism in the pathophysiology of metabolic complications caused by sex steroids is under investigation. The gut microbiota represents a complex microbial ecosystem involved in energy metabolism, immune response, nutrition acquisition, and the health of host organisms. Gender-specific differences in composition are present between females and males. The purpose of this study was to use cross-sex fecal microbiota transplantation (FMT) for the detection of sex-dependent metabolic, hormonal, and gut microbiota changes in female and male recipients. Healthy non-obese female and male Wistar rats were divided into donor, same-sex, and cross-sex recipient groups. After a 30-day period of FMT administration, biochemical markers (glucose and lipid metabolism) and sex hormones were measured, and the gut microbiota was analyzed. The cross-sex male recipients displayed a significantly lower testosterone concentration compared to the males that received same-sex FMT. Sex-dependent changes caused by cross-sex FMT were detected, while several bacterial taxa correlated with plasma testosterone levels. This study represents the first to study the effect of cross-sex changes in the gut microbiome concerning metabolic and hormonal changes/status in adult non-obese Wistar rats. Herein, we present cross-sex FMT as a potential tool to modify sex-specific pathologies.

The preliminary evidence on the association of the gut microbiota with stroke risk stratification in South Chinese population

Aims

This study aimed to investigate the association between the gut microbiota and the risk of stroke.

Methods

Faecal samples from 60 participants in South China, including 45 individuals with risk factors for stroke and 15 healthy controls, were collected and subjected to 16S rRNA sequencing. A bioinformatics analysis was performed to characterise the gut microbial diversity and taxonomic compositions at different risk levels (low, moderate, and high) of stroke. Functional prediction and correlation analyses between the microbiota and laboratory markers were performed to explore the potential mechanisms.

Results

A significant difference in beta diversity was observed between the participants from the stroke risk and healthy control groups. Linear discriminant effect size analysis revealed a large number of vascular beneficial bacteria enriched in the participants from the healthy control and low-risk groups, but a few vascular harmful bacteria were more abundant in the participants from the high-risk group than in those from the other groups. In addition, Anaerostipes, Clostridium_XlVb, and Flavonifractor, all of which belonged to the Firmicutes phylum, were enriched in the participants from the low-risk group, and their relative abundances gradually decreased as the stroke risk increased. Spearman's analysis revealed that these outstanding microbiota correlated with the levels of triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, white blood cells, neutrophils, and carotid intima-media thickness.

Conclusion

The preliminary evidence suggests that gut microbiota is associated with stroke risk. It potentially ameliorates atherosclerosis by targeting lipid metabolism and inflammation. This provides novel insights into the early screening of stroke risk and primary prevention.

Gut liver brain axis in diseases: the implications for therapeutic interventions

Gut-liver-brain axis is a three-way highway of information interaction system among the gastrointestinal tract, liver, and nervous systems. In the past few decades, breakthrough progress has been made in the gut liver brain axis, mainly through understanding its formation mechanism and increasing treatment strategies. In this review, we discuss various complex networks including barrier permeability, gut hormones, gut microbial metabolites, vagus nerve, neurotransmitters, immunity, brain toxic metabolites, β-amyloid (Aβ) metabolism, and epigenetic regulation in the gut-liver-brain axis. Some therapies containing antibiotics, probiotics, prebiotics, synbiotics, fecal microbiota transplantation (FMT), polyphenols, low FODMAP diet and nanotechnology application regulate the gut liver brain axis. Besides, some special treatments targeting gut-liver axis include farnesoid X receptor (FXR) agonists, takeda G protein-coupled receptor 5 (TGR5) agonists, glucagon-like peptide-1 (GLP-1) receptor antagonists and fibroblast growth factor 19 (FGF19) analogs. Targeting gut-brain axis embraces cognitive behavioral therapy (CBT), antidepressants and tryptophan metabolism-related therapies. Targeting liver-brain axis contains epigenetic regulation and Aβ metabolism-related therapies. In the future, a better understanding of gut-liver-brain axis interactions will promote the development of novel preventative strategies and the discovery of precise therapeutic targets in multiple diseases.

Disentangling the age-related manner in the associations between gut microbiome and women's health: a multi-cohort microbiome study

Women's health encompasses life-course healthcare, and mounting evidence emphasizes the pivotal contribution of gut microbiota. Therefore, understanding the temporal dynamics of gut microbiota and how age influences disease-gut microbiota associations is essential for improving women's health. By analyzing metagenomic data from 3625 healthy women, we revealed significant effects of age on gut microbiota and age-dependent patterns in microbial features, such as relative abundance, Shannon index, and microbial network properties. Additionally, declining trends in the predictive accuracy of gut microbiota for age groups were shown using iterative sub-sampling based random forest (ISSRF) model. Age-specific species markers were also identified, many of which were shared across age groups. To investigate the influence of age on disease-gut microbiota associations, metagenomic data from 681 women with various disease conditions and 491 matched healthy controls were collected. A substantial proportion of species markers for inflammatory bowel disease (IBD), type 2 diabetes (T2D), atherosclerotic cardiovascular disease (ACVD), and impaired glucose tolerance (IGT) differed in relative abundance across age groups, and were also age-specific species markers. Besides, the microbiota-based probabilities of IBD and ACVD were positively correlated with age. Furthermore, the age specificity of disease-gut microbiota associations was explored using the ISSRF model. Associations between IBD and gut microbiota were age-specific, with reduced stability of disease species markers in childhood and adolescence, possibly due to decrease in the effect size between patients and controls. Our findings provided valuable insights into promoting healthy aging and developing personalized healthcare strategies for women.

Microbiota from Alzheimer's patients induce deficits in cognition and hippocampal neurogenesis

Alzheimer's disease is a complex neurodegenerative disorder leading to a decline in cognitive function and mental health. Recent research has positioned the gut microbiota as an important susceptibility factor in Alzheimer's disease by showing specific alterations in the gut microbiome composition of Alzheimer's patients and in rodent models. However, it is unknown whether gut microbiota alterations are causal in the manifestation of Alzheimer's symptoms. To understand the involvement of Alzheimer's patient gut microbiota in host physiology and behaviour, we transplanted faecal microbiota from Alzheimer's patients and age-matched healthy controls into microbiota-depleted young adult rats. We found impairments in behaviours reliant on adult hippocampal neurogenesis, an essential process for certain memory functions and mood, resulting from Alzheimer's patient transplants. Notably, the severity of impairments correlated with clinical cognitive scores in donor patients. Discrete changes in the rat caecal and hippocampal metabolome were also evident. As hippocampal neurogenesis cannot be measured in living humans but is modulated by the circulatory systemic environment, we assessed the impact of the Alzheimer's systemic environment on proxy neurogenesis readouts. Serum from Alzheimer's patients decreased neurogenesis in human cells in vitro and were associated with cognitive scores and key microbial genera. Our findings reveal for the first time, that Alzheimer's symptoms can be transferred to a healthy young organism via the gut microbiota, confirming a causal role of gut microbiota in Alzheimer's disease, and highlight hippocampal neurogenesis as a converging central cellular process regulating systemic circulatory and gut-mediated factors in Alzheimer's.

Effects of the multidomain intervention with nutritional supplements on cognition and gut microbiome in early symptomatic Alzheimer's disease: a randomized controlled trial

Background

The SoUth Korean study to PrEvent cognitive impaiRment and protect BRAIN health through lifestyle intervention in at-risk elderly people (SUPERBRAIN) is a part of the World-Wide Finnish Geriatric Intervention Study to Prevent Cognitive Impairment and Disability (WW-FINGERS) network. This study aimed to demonstrate the effects of the SUPERBRAIN-based multidomain intervention with nutritional supplements in amyloid positive emission tomography (PET) proven early symptomatic Alzheimer's disease patients.

Methods

Forty-six participants who were diagnosed with mild cognitive impairment or mild dementia and were positive in the amyloid PET study randomized into three groups: group A, the multidomain intervention with nutritional supplements; group B, nutritional supplements only; and a control group. The primary outcome was a change in the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) total scale index score after an 8-week intervention. Secondary outcomes, including gut microbiome data, were also analyzed.

Results

The RBANS total scale index score improved significantly in group A compared with group B (p < 0.032) and compared with the control group (p < 0.001). After intervention, beta diversity of the gut microbiome between group A and the control group increased, and patients in group A were more enriched with Bifidobacterium.

Conclusion

SUPERBRAIN-based multidomain intervention with nutritional supplements improves cognition and gut microbiota in patients with early symptomatic Alzheimer's disease who were amyloid-positive by PET.

Sex-based influential factors for dental caries in patients with schizophrenia

BACKGROUND

Schizophrenia is a common mental disorder that seriously affects patients' daily lives and brings heavy psychological and economic burdens to their families and society. The oral problems of patients with schizophrenia are gradually gaining attention, among which dental caries are among the most common oral diseases. Sex differences may be related not only to the various clinical symptoms of schizophrenia but also to different oral hygiene statuses; therefore, the main purpose of this paper is to investigate sex differences related to influencing factors for dental caries in patients with schizophrenia.

METHOD

Inpatients with schizophrenia over 18 years old were included in this study, and multidimensional indicators such as demographics, symptom and cognitive impairment assessments, medications, and the caries index of decayed, missing, and filled teeth (DMFT) were collected. An analysis of sex-based influential factors for dental caries in schizophrenia patients was performed.

RESULTS

Four-hundred and ninety-six patients with schizophrenia were included, with a mean age of 46.73 ± 12.23 years, of which 142 were females and 354 were males. The mean DMFT was significantly higher in males (8.81 ± 8.50) than in females (5.63 ± 6.61, p < 0.001), and the odd ratio of caries in males to females was significantly higher as well (OR = 2.305, p < 0.001). The influential factors of caries in male patients were independently associated with age and smoking status, in which current smokers were at the highest risk for developing caries, and different smoking statuses had various influencing factors for caries. The influencing factors for caries in female patients were independently associated with age, antipsychotic dose, PANSS-positive symptoms, and MMSE levels.

CONCLUSION

Our findings suggest sex differences exist among influential factors for caries in patients with schizophrenia. These risk factors may even be associated with and affect the treatment and prognosis of psychiatric symptoms in patients. Therefore, oral hygiene management of patients with schizophrenia should be enhanced. These differential factors provide new visions and ideas for formulating individual interventions, treatments, and care priorities.

Current Discoveries and Future Implications of Eating Disorders

Eating disorders (EDs) are characterized by severe disturbances in eating behaviors and can sometimes be fatal. Eating disorders are also associated with distressing thoughts and emotions. They can be severe conditions affecting physical, psychological, and social functions. Preoccupation with food, body weight, and shape may also play an important role in the regulation of eating disorders. Common eating disorders have three major types: anorexia nervosa (AN), bulimia nervosa (BN), and binge eating disorder (BED). In some cases, EDs can have serious consequences for an individual's physical and mental health. These disorders often develop during adolescence or early adulthood and affect both males and females, although they are more commonly diagnosed in young adult females. Treatment for EDs typically involves a combination of therapy, nutrition counseling, and medical care. In this narrative review, the authors summarized what is known of EDs and discussed the future directions that may be worth exploring in this emerging area.

Sex and gender as critical and distinct contributors to the human brain-gut-microbiome axis

The brain-gut-microbiome axis (BGMA) is a pivotal contributor to human health. A large body of research, especially from animal models, has revealed bidirectional, causal relationships between the BGMA and sex. In particular, sex steroids appear to be affected by the BGMA, to influence the BGMA, and to moderate environmental effects on the BGMA. However, animal research on the relationship between sex and the BGMA has not translated well to human models. We contend that this is due in part to an oversimplified approach to sex: although BGMA researchers have traditionally approached sex as a unidimensional, dichotomous variable, it is in fact multidimensional and is comprised of both multi-categorical and continuous dimensions. We also contend that research on the BGMA in humans should approach gender as a variable that is distinct from sex and that gender may influence the BGMA through pathways that are independent from the effects of sex alone. Research practices that consider the complexity and distinctiveness of sex and gender in relation to the human BGMA will not only yield improved understanding of this consequential system, but will also enhance the development of treatments for adverse health outcomes with BGMA-related etiologies. We conclude with recommendations for the implementation of such practices.

Sex differences in long-term effects of collagen-induced arthritis in middle-aged mice

Introduction: Rheumatoid arthritis (RA) is a chronic inflammatory disorder with high prevalence among middle-aged women. Collagen-induced arthritis (CIA) is the most widely used animal model of RA, however, sex differences and long-term effects of CIA in mice are poorly described in the literature. Aim: Therefore, the present study aimed to analyze the long-term effects of CIA on the joints of middle-aged mice of both sexes and to describe potential sex differences. Materials and methods: CIA was induced in middle-aged DBA/1J mice by immunization with bovine type II collagen and complete Freund's adjuvant. Saline was administered to control mice. Arthritis score assessment, plethysmometry, and thermal imaging of the joints were performed weekly for 15 weeks. Locomotor activity, micro-computed tomography, joint histology and biochemical analyses were performed at the end of the experiment. Results: Our results indicate a similar prevalence of arthritis in both sexes of mice-67% (8/12) of females and 89% (8/9) males with an earlier onset in males (day 14 vs. day 35). After the arthritis scores peaked on day 56 for males and day 63 for females, they steadily declined until the end of the experiment on day 105. A similar dynamics was observed in paw volume and temperature analyzing different aspects of joint inflammation. Long-term consequences including higher proteinuria (by 116%), loss of bone density (by 33.5%) and joint damage in terms of synovial hyperplasia as well as bone and cartilage erosions were more severe in CIA males compared to CIA females. There were no significant differences in locomotor activity between CIA mice and CTRL mice of any sex. Conclusion: This is the first study to describe the long-term effects of the CIA model in terms of sex differences in DBA/1J mice. Our results indicate sex differences in the dynamics, but not in the extent of arthritis. An earlier onset of arthritis and more severe consequences on joints, bones and kidneys were found in males. The underlying immune pathomechanisms responsible for the limited duration of the arthritis symptoms and the opposite sex difference in comparison to RA patients require further investigation.

Microbiota Profile of the Nasal Cavity According to Lifestyles in Healthy Adults in Santiago, Chile

BACKGROUND

The respiratory microbiome is dynamic, varying between anatomical niches, and it is affected by various host and environmental factors, one of which is lifestyle. Few studies have characterized the upper respiratory tract microbiome profile according to lifestyle. We explored the association between lifestyles and microbiota profiles in the upper respiratory tract of healthy adults.

METHODS

We analyzed nasal samples from 110 healthy adults who were living in Santiago, Chile, using 16S ribosomal RNA gene-sequencing methods. Volunteers completed a structured questionnaire about lifestyle.

RESULTS

The composition and abundance of taxonomic groups varied across lifestyle attributes. Additionally, multivariate models suggested that alpha diversity varied in the function of physical activity, nutritional status, smoking, and the interaction between nutritional status and smoking, although the significant impact of those variables varied between women and men. Although physical activity and nutritional status were significantly associated with all indexes of alpha diversity among women, the diversity of microbiota among men was associated with smoking and the interaction between nutritional status and smoking.

CONCLUSIONS

The alpha diversity of nasal microbiota is associated with lifestyle attributes, but these associations depend on sex and nutritional status. Our results suggest that future studies of the airway microbiome may provide a better resolution if data are stratified for differences in sex and nutritional status.

Microbiota and nutrition as risk and resiliency factors following prenatal alcohol exposure

Alcohol exposure in adulthood can result in inflammation, malnutrition, and altered gastroenteric microbiota, which may disrupt efficient nutrient extraction. Clinical and preclinical studies have documented convincingly that prenatal alcohol exposure (PAE) also results in persistent inflammation and nutrition deficiencies, though research on the impact of PAE on the enteric microbiota is in its infancy. Importantly, other neurodevelopmental disorders, including autism spectrum and attention deficit/hyperactivity disorders, have been linked to gut microbiota dysbiosis. The combined evidence from alcohol exposure in adulthood and from other neurodevelopmental disorders supports the hypothesis that gut microbiota dysbiosis is likely an etiological feature that contributes to negative developmental, including neurodevelopmental, consequences of PAE and results in fetal alcohol spectrum disorders. Here, we highlight published data that support a role for gut microbiota in healthy development and explore the implication of these studies for the role of altered microbiota in the lifelong health consequences of PAE.

Neurodegenerative and Neurodevelopmental Diseases and the Gut-Brain Axis: The Potential of Therapeutic Targeting of the Microbiome

The human gut microbiome contains the largest number of bacteria in the body and has the potential to greatly influence metabolism, not only locally but also systemically. There is an established link between a healthy, balanced, and diverse microbiome and overall health. When the gut microbiome becomes unbalanced (dysbiosis) through dietary changes, medication use, lifestyle choices, environmental factors, and ageing, this has a profound effect on our health and is linked to many diseases, including lifestyle diseases, metabolic diseases, inflammatory diseases, and neurological diseases. While this link in humans is largely an association of dysbiosis with disease, in animal models, a causative link can be demonstrated. The link between the gut and the brain is particularly important in maintaining brain health, with a strong association between dysbiosis in the gut and neurodegenerative and neurodevelopmental diseases. This link suggests not only that the gut microbiota composition can be used to make an early diagnosis of neurodegenerative and neurodevelopmental diseases but also that modifying the gut microbiome to influence the microbiome-gut-brain axis might present a therapeutic target for diseases that have proved intractable, with the aim of altering the trajectory of neurodegenerative and neurodevelopmental diseases such as Alzheimer's disease, Parkinson's disease, multiple sclerosis, autism spectrum disorder, and attention-deficit hyperactivity disorder, among others. There is also a microbiome-gut-brain link to other potentially reversible neurological diseases, such as migraine, post-operative cognitive dysfunction, and long COVID, which might be considered models of therapy for neurodegenerative disease. The role of traditional methods in altering the microbiome, as well as newer, more novel treatments such as faecal microbiome transplants and photobiomodulation, are discussed.

Sex-dependent gut microbiota-brain-cognition associations: a multimodal MRI study

BACKGROUND

There is bidirectional communication between the gut microbiota and the brain. Empirical evidence has demonstrated sex differences in both the gut microbiome and the brain. However, the effects of sex on the gut microbiota-brain associations have yet to be determined. We aim to elucidate the sex-specific effects of gut microbiota on brain and cognition.

METHODS

One hundred fifty-seven healthy young adults underwent brain structural, perfusion, functional and diffusion MRIs to measure gray matter volume (GMV), cerebral blood flow (CBF), functional connectivity strength (FCS) and white matter integrity, respectively. Fecal samples were collected and 16S amplicon sequencing was utilized to assess gut microbial diversity. Correlation analyses were conducted to test for sex-dependent associations between microbial diversity and brain imaging parameters, and mediation analysis was performed to further characterize the gut microbiota-brain-cognition relationship.

RESULTS

We found that higher gut microbial diversity was associated with higher GMV in the right cerebellum VI, higher CBF in the bilateral calcarine sulcus yet lower CBF in the left superior frontal gyrus, higher FCS in the bilateral paracentral lobule, and lower diffusivity in widespread white matter regions in males. However, these associations were absent in females. Of more importance, these neuroimaging biomarkers significantly mediated the association between gut microbial diversity and behavioral inhibition in males.

CONCLUSIONS

These findings highlight sex as a potential influential factor underlying the gut microbiota-brain-cognition relationship, and expose the gut microbiota as a biomarker-driven and sex-sensitive intervention target for mental disorders with abnormal behavioral inhibition.

The Hypothalamic-Pituitary-Gonadal Axis in Men with Schizophrenia

Schizophrenia is a severe mental disorder with a chronic, progressive course. The etiology of this condition is linked to the interactions of multiple genes and environmental factors. The earlier age of onset of schizophrenia, the higher frequency of negative symptoms in the clinical presentation, and the poorer response to antipsychotic treatment in men compared to women suggests the involvement of sex hormones in these processes. This article aims to draw attention to the possible relationship between testosterone and some clinical features in male schizophrenic patients and discuss the complex nature of these phenomena based on data from the literature. PubMed, Web of Science, and Google Scholar databases were searched to select the papers without limiting the time of the publications. Hormone levels in the body are regulated by many organs and systems, and take place through the neuroendocrine, hormonal, neural, and metabolic pathways. Sex hormones play an important role in the development and function of the organism. Besides their impact on secondary sex characteristics, they influence brain development and function, mood, and cognition. In men with schizophrenia, altered testosterone levels were noted. In many cases, evidence from available single studies gave contradictory results. However, it seems that the testosterone level in men affected by schizophrenia may differ depending on the phase of the disease, types of clinical symptoms, and administered therapy. The etiology of testosterone level disturbances may be very complex. Besides the impact of the illness (schizophrenia), stress, and antipsychotic drug-induced hyperprolactinemia, testosterone levels may be influenced by, i.a., obesity, substances of abuse (e.g., ethanol), or liver damage.

Sex differences in neuroimmunoendocrine communication. Involvement on longevity

Endocrine, nervous, and immune systems work coordinately to maintain the global homeostasis of the organism. They show sex differences in their functions that, in turn, contribute to sex differences beyond reproductive function. Females display a better control of the energetic metabolism and improved neuroprotection and have more antioxidant defenses and a better inflammatory status than males, which is associated with a more robust immune response than that of males. These differences are present from the early stages of life, being more relevant in adulthood and influencing the aging trajectory in each sex and may contribute to the different life lifespan between sexes.

Intersection of Sex and Depression: Pathogenesis, Presentation, and Treatments

Major Depressive Disorder (MDD) is a highly prevalent, debilitating disorder. According to the World Health Organization, approximately 5% of adults suffer from depression worldwide and more women than men are affected. Yet, we have a very limited understanding of the pathogenesis of the disease, how sex and genetics influence the pathophenotype of MDD, and how they contribute to the responses to pharmacological treatment. This chapter addresses key theories about the etiology of depression, the variations in epidemiology and presentation, and the treatment options with respect to sex and gender. Additionally, we discuss the emerging wave of treatment modalities, diagnosis, and research focusing on MDD.

Sex differences in factors influencing hospital-acquired pneumonia in schizophrenia patients receiving modified electroconvulsive therapy

BACKGROUND

Sex differences may be presented in the clinical features or symptoms of schizophrenia patients but also affect the occurrence of hospital-acquired pneumonia (HAP). Modified electroconvulsive therapy (mECT) is a common treatment method for schizophrenia, used in combination with antipsychotics. This retrospective research explores the sex difference in HAP affecting patients with schizophrenia who have received mECT treatment during hospitalization.

METHODS

We included schizophrenia inpatients treated with mECT and antipsychotics between January 2015 and April 2022. Blood-related and demographic data collected on admission were analyzed. Influencing factors of HAP in male and female groups were assessed separately.

RESULTS

A total of 951 schizophrenia patients treated with mECT were enrolled in the study, including 375 males and 576 females, of which 62 patients experienced HAP during hospitalization. The risk period of HAP in these patients was found to be the first day after each mECT treatment and the first three sessions of mECT treatment. Statistically significant differences in the incidence of HAP were identified in male vs. female groups, with an incidence in men about 2.3 times higher than that in women (P < 0.001). Lower total cholesterol (Z = -2.147, P = 0.032) and the use of anti-parkinsonian drugs (χ² = 17.973, P < 0.001) were found to be independent risk factors of HAP in male patients, while lower lymphocyte count (Z = -2.408, P = 0.016), hypertension (χ² = 9.096, P = 0.003), and use of sedative-hypnotic drugs (χ² = 13.636, P < 0.001) were identified in female patients.

CONCLUSION

Influencing factors of HAP in schizophrenia patients treated with mECT have gender differences. The first day after each mECT treatment and the first three sessions of mECT treatment were identified to have the greatest risk for HAP development. Therefore, it would be imperative to monitor clinical management and medications during this period according to these gender differences.

Mechanism and potential treatments for gastrointestinal dysfunction in patients with COVID-19

The global coronavirus disease 2019 (COVID-19) has become one of the biggest threats to the world since 2019. The respiratory and gastrointestinal tracts are the main targets for severe acute respiratory syndrome coronavirus 2 infection for they highly express angiotensin-converting enzyme-2 and transmembrane protease serine 2. In patients suffering from COVID-19, gastrointestinal symptoms have ranged from 12% to 61%. Anorexia, nausea and/or vomiting, diarrhea, and abdominal pain are considered to be the main gastrointestinal symptoms of COVID-19. It has been reported that the direct damage of intestinal mucosal epithelial cells, malnutrition, and intestinal flora disorders are involved in COVID-19. However, the underlying mechanisms remain unclear. Thus, in this study, we reviewed and discussed the correlated mechanisms that cause gastrointestinal symptoms in order to help to develop the treatment strategy and build an appropriate guideline for medical workers.

Gut Microbiota and Fear Processing in Women Affected by Obesity: An Exploratory Pilot Study

The microbiota–gut–brain axis extends beyond visceral perception, influencing higher-order brain structures, and ultimately psychological functions, such as fear processing. In this exploratory pilot study, we attempted to provide novel experimental evidence of a relationship between gut microbiota composition and diversity, and fear-processing in obesity, through a behavioral approach. Women affected by obesity were enrolled and profiled for gut microbiota, through 16S rRNA amplicon sequencing. Moreover, we tested their ability to recognize facial fearful expressions through an implicit-facial-emotion-recognition task. Finally, a traditional self-report questionnaire was used to assess their temperamental traits. The participants exhibited an unbalanced gut microbiota profile, along with impaired recognition of fearful expressions. Interestingly, dysbiosis was more severe in those participants with altered behavioral performance, with a decrease in typically health-associated microbes, and an increase in the potential pathobiont, Collinsella. Moreover, Collinsella was related to a lower expression of the persistence temperamental trait, while a higher expression of the harm-avoidance temperament, related to fear-driven anxiety symptoms, was linked to Lactobacillus. Once confirmed, our findings could pave the way for the design of innovative microbiome-based strategies for the treatment of psychological and emotional difficulties by mitigating obesity-related consequences and behaviors.

Dietary EVOO Polyphenols and Gut Microbiota Interaction: Are There Any Sex/Gender Influences?

Accumulating evidence indicates that regular consumption of extra virgin olive oil (EVOO), the main source of fat in the Mediterranean diet, is associated with beneficial health effects and a reduced risk of developing chronic degenerative disorders. The beneficial effects of EVOO can be attributed to its unique composition in monounsaturated fats and phenolic compounds that provide important antioxidant, anti-inflammatory, and immune-modulating activities. On the other hand, it is well known that the gut microbiota has several important roles in normal human physiology, and its composition can be influenced by a multitude of environmental and lifestyle factors, among which dietary components play a relevant role. In the last few years, the two-way interaction between polyphenols, including those in EVOO, and the gut microbiota, i.e., the modulation of the microbiota by polyphenols and that of polyphenol metabolism and bioavailability by the microbiota, has attracted growing attention, being potentially relevant to explain the final effects of polyphenols, as well as of the microbiota profile. Furthermore, sex and gender can affect dietary habits, polyphenol intake, and nutrient metabolism. Lastly, it has been recently suggested that differences in gut microbiota composition could be involved in the unequal incidence of metabolic diseases observed between women and men, due to sex-dependent effects on shaping gut microbiota profiles according to diet. This review summarizes the most recent studies on the relationship between EVOO polyphenols and the gut microbiota, taking into account possible influences of sex and gender in modulating such an interaction.