Molecular interactions between the intestinal microbiota and the host

The association between prenatal antibiotic exposure and adverse long-term health outcomes in children: A systematic review and meta-analysis

BACKGROUND

Antibiotics are the most commonly prescribed drugs during pregnancy. The long-term health risks to children associated with prenatal antibiotic exposure are uncertain.

OBJECTIVE

To identify the association between prenatal antibiotics and adverse long-term health outcomes in children.

METHODS

A systematic search was done to identify original studies investigating the association between prenatal antibiotic exposure and adverse long-term health outcomes in children. Studies were excluded if: (i) antibiotics were only given during delivery or (ii) the outcome was present before antibiotic exposure.

RESULTS

We included 158 studies, reporting 23 outcomes in 21,943,763 children, in our analysis. For the following adverse health outcomes, there was a significant association with antibiotic exposure found in two or more studies: atopic dermatitis (OR 1.27, 95% CI 1.06-1.52, p=0.01), food allergies (OR 1.25, 95% CI 1.09-1.44, p<0.01), allergic rhinoconjunctivitis (OR 1.16, 95% CI 1.15-1.17, p<0.01), wheezing (OR 1.39, 95% CI 1.14-1.69, p<0.01), asthma (OR 1.36, 95% CI 1.24-1.50, p<0.01), obesity (OR 1.36, 95% CI 1.12-1.64, p<0.01), cerebral palsy (OR 1.25, 95% CI 1.10-1.43, p<0.01), epilepsy or febrile seizure (OR 1.16, 95% CI 1.08-1.24, p<0.01), and cancer (OR 1.13, 95% CI 1.01-1.26, p=0.04).

CONCLUSION

Although causality cannot be implied, these findings support antibiotic stewardship efforts to ensure judicious use of antibiotics during pregnancy to avoid potential long-term health risks.

Gut microbiome-gut brain axis-depression: interconnection

OBJECTIVES

The relationship between the gut microbiome and mental health, particularly depression, has gained significant attention. This review explores the connection between microbial metabolites, dysbiosis, and depression. The gut microbiome, comprising diverse microorganisms, maintains physiological balance and influences health through the gut-brain axis, a communication pathway between the gut and the central nervous system.

METHODS

Dysbiosis, an imbalance in the gut microbiome, disrupts this axis and worsens depressive symptoms. Factors like diet, antibiotics, and lifestyle can cause this imbalance, leading to changes in microbial composition, metabolism, and immune responses. This imbalance can induce inflammation, disrupt neurotransmitter regulation, and affect hormonal and epigenetic processes, all linked to depression.

RESULTS

Microbial metabolites, such as short-chain fatty acids and neurotransmitters, are key to gut-brain communication, influencing immune regulation and mood. The altered production of these metabolites is associated with depression. While progress has been made in understanding the gut-brain axis, more research is needed to clarify causative relationships and develop new treatments. The emerging field of psychobiotics and microbiome-targeted therapies shows promise for innovative depression treatments by harnessing the gut microbiome's potential.

CONCLUSIONS

Epigenetic mechanisms, including DNA methylation and histone modifications, are crucial in how the gut microbiota impacts mental health. Understanding these mechanisms offers new prospects for preventing and treating depression through the gut-brain axis.

Differences in Gut Microbial Composition and Characteristics Among Three Populations of the Bamboo Pitviper (Viridovipera stejnegeri)

The gut microbiota contributes to host health by facilitating nutrient uptake, digestion, energy metabolism, intestinal development, vitamin synthesis, and immunomodulation, and plays an important role in the growth and reproduction of the animal itself. Considering the paucity of research on the gut microbiota of wild snakes, this study focused on bamboo pitviper (Viridovipera stejnegeri) populations from Anhui, Guizhou, and Hunan, with multiple fecal samples collected from each population (six, five, and three, respectively). Total microbial DNA was extracted from the fecal samples using metagenomic next-generation sequencing and differences in gut microbial composition, abundance, and carbohydrate-active enzymes (CAZymes) were analyzed and compared among the three populations. Results showed no significant variance in the α-diversity of the gut microbes across the three populations, while principal coordinate analysis revealed significant differences in gut microbe composition. The four most abundant phyla in the gut microbiota of V. stejnegeri were Pseudomonadota, Bacteroidota, Actinomycetota, and Bacillota, while the four most abundant genera were Salmonella, Citrobacter, Bacteroides, and Yokenella. Linear discriminant analysis effect size demonstrated notable differences in gut microbial abundance among the three populations. Marked differences in CAZyme abundance were also observed across the microbial communities. Future studies should incorporate diverse ecological factors to evaluate their influence on the composition and function of gut microbiota.

The microbiota: a key regulator of health, productivity, and reproductive success in mammals

The microbiota, intensely intertwined with mammalian physiology, significantly impacts health, productivity, and reproductive functions. The normal microbiota interacts with the host through the following key mechanisms: acting as a protective barrier against pathogens, maintain mucosal barrier integrity, assisting in nutrient metabolism, and modulating of the immune response. Therefore, supporting growth and development of host, and providing protection against pathogens and toxic substances. The microbiota significantly influences brain development and behavior, as demonstrated by comprehensive findings from controlled laboratory experiments and human clinical studies. The prospects suggested that gut microbiome influence neurodevelopmental processes, modulate stress responses, and affect cognitive function through the gut-brain axis. Microbiota in the gastrointestinal tract of farm animals break down and ferment the ingested feed into nutrients, utilize to produce meat and milk. Among the beneficial by-products of gut microbiota, short-chain fatty acids (SCFAs) are particularly noteworthy for their substantial role in disease prevention and the promotion of various productive aspects in mammals. The microbiota plays a pivotal role in the reproductive hormonal systems of mammals, boosting reproductive performance in both sexes and fostering the maternal-infant connection, thereby becoming a crucial factor in sustaining mammalian existence. The microbiota is a critical factor influencing reproductive success and production traits in mammals. A well-balanced microbiome improves nutrient absorption and metabolic efficiency, leading to better growth rates, increased milk production, and enhanced overall health. Additionally, it regulates key reproductive hormones like estrogen and progesterone, which are essential for successful conception and pregnancy. Understanding the role of gut microbiota offers valuable insights for optimizing breeding and improving production outcomes, contributing to advancements in agriculture and veterinary medicine. This study emphasizes the critical ecological roles of mammalian microbiota, highlighting their essential contributions to health, productivity, and reproductive success. By integrating human and veterinary perspectives, it demonstrates how microbial communities enhance immune function, metabolic processes, and hormonal regulation across species, offering insights that benefit both clinical and agricultural advancements.

Effects of forages on the microbiota of crossed sheep on cold Plateau

Diet is an important component to influence microbiota, there are less data available about the microbiome of Suffolk cross with Tibetan (SCT) animals with different fodders. The current study was conducted for comparing the fungi microbiota in SCT sheep fed with different forages. Sequencing of ileum samples from sheep groups of AH (alfalfa and oat grass), BH (mixture of grass and concentrated feeds), CH (concentrated feed I), DH (concentrated feed II) and EH (concentrated feed III) achieved 3,171,271 raw and 2,719,649 filtered sequences. Concentrated feeds changed fungi microbiota in SCT sheep with three phyla and 47 genera significantly different among the groups. Genera include positive genus of Scytalidium and negative fungi of Sarocladium, Kazachstania, Gibberella, Scytalidium, Candida, Wickerhamomyces. The findings of our study will contribute to efficient feeding of SCT sheep at cold plateau areas.

Specific gut microbiome's role in skin pigmentation: insights from SCARB1 mutants in Oujiang colour common carp

AIMS

Beyond the pivotal roles of the gut microbiome in initiating physiological processes and modulating genetic factors, a query persists: Can a single gene mutation alter the abundance of the gut microbiome community? Not only this, but the intricate impact of gut microbiome composition on skin pigmentation has been largely unexplored.

METHODS AND RESULTS

Based on these premises, our study examines the abundance of lipase-producing gut microbes about differential gene expression associated with bile acid synthesis and lipid metabolism-related blood metabolites in red (whole wild) and white (whole white wild and SCARB1-/- mutant) Oujiang colour common carp. Following the disruption of the SCARB1 gene in the resulting mutant fish with white body colour (SCARB1-/-), there is a notable decrease in the abundance of gut microbiomes (Bacillus, Staphylococcus, Pseudomonas, and Serratia) associated with lipase production. This reduction parallels the downregulation seen in wild-type white body colour fish (WW), as contrasting to the wild-type red body colour fish (WR). Meanwhile, in SCARB1-/- fish, there was a downregulation noted not only at the genetic and metabolic levels but also a decrease in lipase-producing bacteria. This consistency with WW contrasts significantly with WR. Similarly, genes involved in the bile acid synthesis pathway, along with blood metabolites related to lipid metabolism, exhibited downregulation in SCARB1-/- fish.

CONCLUSIONS

The SCARB1 knockout gene blockage led to significant alterations in the gut microbiome, potentially influencing the observed reduction in carotenoid-associated skin pigmentation. Our study emphasizes that skin pigmentation is not only impacted by genetic factors but also by the gut microbiome. Meanwhile, the gut microbiome's adaptability can be rapidly shaped and may be driven by specific single-gene variations.

Probiotics in miRNA-Mediated Regulation of Intestinal Immune Homeostasis in Pigs: A Physiological Narrative

The microbiota plays a crucial role in maintaining the host's intestinal homeostasis, influencing numerous physiological functions. Various factors, including diet, stress, and antibiotic use, can lead to such imbalances. Probiotics have been shown to restore the microbiota, contributing to maintaining this balance. For instance, the weaning stage in piglets is crucial; this transition can cause unfavorable changes that may contribute to the onset of diarrhea. Probiotic supplementation has increased due to its benefits. However, its mechanism of action is still controversial; one involves the regulation of intestinal immunity. When recognized by immune system cells through membrane receptors, probiotics activate intracellular signaling pathways that lead to changes in gene expression, resulting in an anti-inflammatory response. This complex regulatory system involves transcriptional and post-transcriptional mechanisms, including the modulation of various molecules, emphasizing microRNAs. They have emerged as important regulators of innate and adaptive immune responses. Analyzing these mechanisms can enhance our understanding of probiotic-host microbiota interactions, providing insights into their molecular functions. This knowledge can be applied not only in the swine industry, but also in studying microbiota-related disorders. Moreover, these studies serve as animal models, helping to understand better conditions such as inflammatory bowel disease and other related disorders.

The Leaky Gut and Human Diseases: "Can't Fill the Cup if You Don't Plug the Holes First"

BACKGROUND

The gut barrier is a sophisticated and dynamic system that forms the frontline defense between the external environment and the body's internal milieu and includes various structural and functional components engaged not only in digestion and nutrient absorption but also in immune regulation and overall health maintenance.

SUMMARY

When one or more components of the intestinal barrier lose their structure and escape their function, this may result in a leaky gut. Mounting evidence emphasizes the crucial role of the gut microbiome in preserving the integrity of the gut barrier and provides insights into the pathophysiological implications of conditions related to leaky gut in humans. Assessment of intestinal permeability has evolved from invasive techniques to noninvasive biomarkers, but challenges remain in achieving consensus about the best testing methods and their accuracy. Research on the modulation of gut permeability is just starting, and although no medical guidelines for the treatment of leaky gut syndrome are available, several treatment strategies are under investigation with promising results.

KEY MESSAGES

This review discusses the composition of the intestinal barrier, the pathophysiology of the leaky gut and its implications on human health, the measurement of intestinal permeability, and the therapeutic strategies to restore gut barrier integrity.

The impact of antibiotic exposure on antibiotic resistance gene dynamics in the gut microbiota of inflammatory bowel disease patients

Background

While antibiotics are commonly used to treat inflammatory bowel disease (IBD), their widespread application can disturb the gut microbiota and foster the emergence and spread of antibiotic resistance. However, the dynamic changes to the human gut microbiota and direction of resistance gene transmission under antibiotic effects have not been clearly elucidated.

Methods

Based on the Human Microbiome Project, a total of 90 fecal samples were collected from 30 IBD patients before, during and after antibiotic treatment. Through the analysis workflow of metagenomics, we described the dynamic process of changes in bacterial communities and resistance genes pre-treatment, during and post-treatment. We explored potential consistent relationships between gut microbiota and resistance genes, and established gene transmission networks among species before and after antibiotic use.

Results

Exposure to antibiotics can induce alterations in the composition of the gut microbiota in IBD patients, particularly a reduction in probiotics, which gradually recovers to a new steady state after cessation of antibiotics. Network analyses revealed intra-phylum transfers of resistance genes, predominantly between taxonomically close organisms. Specific resistance genes showed increased prevalence and inter-species mobility after antibiotic cessation.

Conclusion

This study demonstrates that antibiotics shape the gut resistome through selective enrichment and promotion of horizontal gene transfer. The findings provide insights into ecological processes governing resistance gene dynamics and dissemination upon antibiotic perturbation of the microbiota. Optimizing antibiotic usage may help limit unintended consequences like increased resistance in gut bacteria during IBD management.

Acute effects of the environmental probiotics Rhodobacter sphaeroides on intestinal bacteria and transcriptome in shrimp Penaeusvannamei

In recent years, a substantial number of studies have been dedicated to exploring the potential benefits of probiotics in aquaculture. Rhodobacter sphaeroides can be used in aquaculture-related environmental bioremediation, and its protein is also used as a feed additive in Penaeus vannamei culture. To investigate the effects of releasing R. sphaeroides as environmental probiotics on P. vannamei, we employed 16S rRNA gene and mRNA transcriptome sequencing. Our study focused on assessing alterations in intestinal bacteria and intestinal gene expression in P. vannamei, establishing correlations between them. Our findings revealed a significant increase in the relative abundances of Rhodobacter, Paracoccus, Sulfitobacter, and other bacterial OTUs within the intestinal bacterial community. Additionally, we observed enhanced complexity and stability in the intestinal bacterial correlation network, indicating improved synergy among bacteria and reduced competition. Moreover, the introduction of R. sphaeroides resulted in the down-regulation of certain immune genes and the up-regulation of genes linked to growth and metabolism in the intestinal tissues of P. vannamei. Importantly, we identified a noteworthy correlation between the changes in intestinal bacteria and these alterations in intestinal tissue gene expressions. By conducting analyses of the intestinal bacterial community and intestinal tissue transcriptome, this study revealed the effects of releasing R. sphaeroides as sediment probiotics in P. vannamei culture water. These results serve as vital scientific references for the application of R. sphaeroides in P. vannamei aquaculture.

Investigating the therapeutic potential of Bifidobacterium breve and Lactobacillus rhamnosus postbiotics through apoptosis induction in colorectal HT-29 cancer cells

Background and Objectives

Colorectal cancer (CRC) is a prevalent form of cancer worldwide. Recent studies suggest that postbiotics derived from probiotic bacteria have the potential as an adjunct therapy for CRC. This study investigates the anti-cancer effects of Bifidobacterium breve (B. breve) and Lactobacillus rhamnosus (L. rhamnosus) postbiotics on the HT-29 cell line.

Materials and Methods

Through MTT and scratch assay, we investigated the anti-proliferation and anti-migration effects of B. breve and L. rhamnosus postbiotics on HT-29 cells. Furthermore, postbiotic-mediated apoptosis was assessed by analyzing the expression of Bax, Bcl-2, and caspase-3. We also investigated the effects of B. breve postbiotics on the expression of three important genes involved in metastasis, including RSPO2, NGF, and MMP7. Consequently, we validated the expression of selected genes in twelve adenocarcinoma tissues.

Results

The results demonstrated the significant impact of postbiotics on HT-29 cells, highlighting their ability to induce anti-proliferation, anti-migration, and apoptosis-related effects. Notably, these effects were more pronounced using B. breve postbiotics than L. rhamnosus. Additionally, B. breve postbiotics could inhibit metastasis through upregulation of RSPO2 while downregulating NGF and MMP7 expression in HT-29 cells.

Conclusion

Our research suggests that postbiotic metabolites may be effective biological products for the prevention and treatment of cancer.

Role of gut-microbiota in disease severity and clinical outcomes

A delicate balance of nutrients, antigens, metabolites and xenobiotics in body fluids, primarily managed by diet and host metabolism, governs human health. Human gut microbiota is a gatekeeper to nutrient bioavailability, pathogens exposure and xenobiotic metabolism. Human gut microbiota starts establishing during birth and evolves into a resilient structure by adolescence. It supplements the host's metabolic machinery and assists in many physiological processes to ensure health. Biotic and abiotic stressors could induce dysbiosis in gut microbiota composition leading to disease manifestations. Despite tremendous scientific advancements, a clear understanding of the involvement of gut microbiota dysbiosis during disease onset and clinical outcomes is still awaited. This would be important for developing an effective and sustainable therapeutic intervention. This review synthesizes the present scientific knowledge to present a comprehensive picture of the role of gut microbiota in the onset and severity of a disease.

Mechanisms of intestinal dysbiosis: new insights into tuft cell functions

Symbiosis between the host and intestinal microbial communities is essential for human health. Disruption in this symbiosis is linked to gastrointestinal diseases, including inflammatory bowel diseases, as well as extra-gastrointestinal diseases. Unbalanced gut microbiome or gut dysbiosis contributes in multiple ways to disease frequency, severity and progression. Microbiome taxonomic profiling and metabolomics approaches greatly improved our understanding of gut dysbiosis features; however, the precise mechanisms involved in gut dysbiosis establishment still need to be clarified. The aim of this review is to present new actors and mechanisms underlying gut dysbiosis formation following parasitic infection or in a context of altered Paneth cells, revealing the existence of a critical crosstalk between Paneth and tuft cells to control microbiome composition.

Chronic Inflammatory Enteropathy and Low-Grade Intestinal T-Cell Lymphoma Are Associated with Altered Microbial Tryptophan Catabolism in Cats

Chronic inflammatory enteropathy (CIE) and low-grade intestinal T-cell lymphoma (LGITL) are common chronic enteropathies (CE) in cats. Enteric microbiota dysbiosis is implicated in the pathogenesis of CE; however, the mechanisms of host-microbiome interactions are poorly understood in cats. Microbial indole catabolites of tryptophan (MICT) are gut bacterial catabolites of tryptophan that are hypothesized to regulate intestinal inflammation and mucosal barrier function. MICTs are decreased in the sera of humans with inflammatory bowel disease and previous studies identified altered tryptophan metabolism in cats with CE. We sought to determine whether MICTs were decreased in cats with CE using archived serum samples from cats with CIE (n = 44) or LGITL (n = 31) and healthy controls (n = 26). Quantitative LC-MS/MS was used to measure serum concentrations of tryptophan, its endogenous catabolites (kynurenine, kynurenate, serotonin) and MICTs (indolepyruvate, indolealdehyde, indoleacrylate, indoleacetamide, indoleacetate, indolelactate, indolepropionate, tryptamine). Serum concentrations of tryptophan, indolepropionate, indoleacrylate, indolealdehyde, indolepyruvate, indolelactate were significantly decreased in the CIE and LGITL groups compared to those in healthy controls. Indolelactate concentrations were significantly lower in cats with LGITL compared to CIE (p = 0.006). Significant correlations were detected among serum MICTs and cobalamin, folate, fPLI, and fTLI. Our findings suggest that MICTs are promising biomarkers to investigate the role of gut bacteria in the pathobiology of chronic enteropathies in cats.

Oral Microbiota: The Influences and Interactions of Saliva, IgA, and Dietary Factors in Health and Disease

Recent advances in metagenomic analyses have made it easier to analyze microbiota. The microbiota, a symbiotic community of microorganisms including bacteria, archaea, fungi, and viruses within a specific environment in tissues such as the digestive tract and skin, has a complex relationship with the host. Recent studies have revealed that microbiota composition and balance particularly affect the health of the host and the onset of disease. Influences such as diet, food preferences, and sanitation play crucial roles in microbiota composition. The oral cavity is where the digestive tract directly communicates with the outside. Stable temperature and humidity provide optimal growth environments for many bacteria. However, the oral cavity is a unique environment that is susceptible to pH changes, salinity, food nutrients, and external pathogens. Recent studies have emphasized the importance of the oral microbiota, as changes in bacterial composition and balance could contribute to the development of systemic diseases. This review focuses on saliva, IgA, and fermented foods because they play critical roles in maintaining the oral bacterial environment by regulating its composition and balance. More attention should be paid to the oral microbiota and its regulatory factors in oral and systemic health.

Molecular Ensembles of Microbiotic Metabolites in Carcinogenesis

The mechanisms of carcinogenesis are extremely complex and involve multiple components that contribute to the malignant cell transformation, tumor growth, and metastasis. In recent decades, there has been a growing interest in the role of symbiotic human microbiota in the regulation of metabolism and functioning of host immune system. The symbiosis between a macroorganism and its microbiota has given rise to the concept of a holoorganism. Interactions between the components of a holoorganism have formed in the process of coevolution, resulting in the acquisition by microbiotic metabolites of a special role of signaling molecules and main regulators of molecular interactions in the holoorganism. As elements of signaling pathways in the host organism, bacterial metabolites have become essential participants in various physiological and pathological processes, including tumor growth. At the same time, signaling metabolites often exhibit multiple effects and impact both the functions of the host cells and metabolic activity and composition of the microbiome. This review discusses the role of microbiotic metabolites in the induction and prevention of malignant transformation of cells in the host organism and their impact on the efficacy of anticancer therapy, with special emphasis on the involvement of some components of the microbial metabolite molecular ensemble in the initiation and progression of tumor growth.

The immunomodulatory roles of the gut microbiome in autoimmune diseases of the central nervous system: Multiple sclerosis as a model

The gut-associated lymphoid tissue is a primary activation site for immune responses to infection and immunomodulation. Experimental evidence using animal disease models suggests that specific gut microbes significantly regulate inflammation and immunoregulatory pathways. Furthermore, recent clinical findings indicate that gut microbes' composition, collectively named gut microbiota, is altered under disease state. This review focuses on the functional mechanisms by which gut microbes promote immunomodulatory responses that could be relevant in balancing inflammation associated with autoimmunity in the central nervous system. We also propose therapeutic interventions that target the composition of the gut microbiota as immunomodulatory mechanisms to control neuroinflammation.

Seeking the Psilocybiome: Psychedelics meet the microbiota-gut-brain axis

Moving towards a systems psychiatry paradigm embraces the inherent complex interactions across all levels from micro to macro and necessitates an integrated approach to treatment. Cortical 5-HT2A receptors are key primary targets for the effects of serotonergic psychedelics. However, the therapeutic mechanisms underlying psychedelic therapy are complex and traverse molecular, cellular, and network levels, under the influence of biofeedback signals from the periphery and the environment. At the interface between the individual and the environment, the gut microbiome, via the gut-brain axis, plays an important role in the unconscious parallel processing systems regulating host neurophysiology. While psychedelic and microbial signalling systems operate over different timescales, the microbiota-gut-brain (MGB) axis, as a convergence hub between multiple biofeedback systems may play a role in the preparatory phase, the acute administration phase, and the integration phase of psychedelic therapy. In keeping with an interconnected systems-based approach, this review will discuss the gut microbiome and mycobiome and pathways of the MGB axis, and then explore the potential interaction between psychedelic therapy and the MGB axis and how this might influence mechanism of action and treatment response. Finally, we will discuss the possible implications for a precision medicine-based psychedelic therapy paradigm.

The need for biomarkers to determine response to enteral nutrition during and after critical illness: an update

PURPOSE OF REVIEW

Biomarkers proposed to provide prognosis or to determine the response to enteral nutrition have been assessed in a number of experimental and clinical studies which are summarized in the current review.

RECENT FINDINGS

There are several pathophysiological mechanisms identified which could provide biomarkers to determine response to enteral nutrition. Several biomarkers have been studied, most of them insufficiently and none of them has made its way to clinical practice. Available studies have mainly assessed a simple association of a biomarker with outcomes, but are less focused on dynamic changes in the biomarker levels. Importantly, studies on pathophysiology and clinical features of gastrointestinal dysfunction, including enteral feeding intolerance, are also needed to explore the mechanisms potentially providing specific biomarkers. Not only an association of the biomarker with any adverse outcome, but also a rationale for repeated assessment to assist in treatment decisions during the course of illness is warranted.

SUMMARY

There is no biomarker currently available to reliably provide prognosis or determine the response to enteral nutrition in clinical practice, but identification of such a biomarker would be valuable to assist in clinical decision-making.

Gut Microbiota Alterations in Trace Amine-Associated Receptor 9 (TAAR9) Knockout Rats

Trace amine-associated receptors (TAAR1-TAAR9) are a family of G-protein-coupled monoaminergic receptors which might have great pharmacological potential. It has now been well established that TAAR1 plays an important role in the central nervous system. Interestingly, deletion of TAAR9 in rats leads to alterations in the periphery. Previously, we found that knockout of TAAR9 in rats (TAAR9-KO rats) decreased low-density lipoprotein cholesterol levels in the blood. TAAR9 was also identified in intestinal tissues, and it is known that it responds to polyamines. To elucidate the role of TAAR9 in the intestinal epithelium, we analyzed TAAR9-co-expressed gene clusters in public data for cecum samples. As identified by gene ontology enrichment analysis, in the intestine, TAAR9 is co-expressed with genes involved in intestinal mucosa homeostasis and function, including cell organization, differentiation, and death. Additionally, TAAR9 was co-expressed with genes implicated in dopamine signaling, which may suggest a role for this receptor in the regulation of peripheral dopaminergic transmission. To further investigate how TAAR9 might be involved in colonic mucosal homeostasis, we analyzed the fecal microbiome composition in TAAR9-KO rats and their wild-type littermates. We identified a significant difference in the number of observed taxa between the microbiome of TAAR9-KO and wild-type rats. In TAAR9-KO rats, the gut microbial community became more variable compared with the wild-type rats. Furthermore, it was found that the family Saccharimonadaceae, which is one of the top 10 most abundant families in TAAR9-KO rat feces, is almost completely absent in wild-type animal fecal samples. Taken together, these data indicate a role of TAAR9 in intestinal function.

The Impact of Sleep Disturbance on Gut Microbiota, Atrial Substrate, and Atrial Fibrillation Inducibility in Mice: A Multi-Omics Analysis

This study examined the effect of sleep disturbance on gut microbiota (GM), atrial substrate, and atrial fibrillation (AF) inducibility. C57BL/6 mice were subjected to six weeks of sleep deprivation (SD) using the method of modified multiple-platform. Transesophageal burst pacing was performed to evaluate AF inducibility. Feces, plasma, and an atrium were collected and analyzed by 16s rRNA sequencing, liquid chromatography−mass spectrometry (LC-MS)-based metabolome, histological studies, and transcriptome. Higher AF inducibility (2/30 of control vs. 15/30 of SD, p = 0.001) and longer AF duration (p < 0.001), concomitant with aggravated fibrosis, collagen, and lipid accumulation, were seen in the SD mice compared to control mice. Meanwhile, elevated alpha diversity, higher abundance of Flavonifractor, Ruminococcus, and Alloprevotella, as well as imbalanced functional pathways, were observed in the gut of SD mice. Moreover, the global patterns for the plasma metabolome were altered, e.g., the decreased butanoate metabolism intermediates in SD mice. In addition, disrupted metabolic homeostasis in the SD atrium, such as fatty acid metabolism, was analyzed by the transcriptome. These results demonstrated that the crosstalk between GM and atrial metabolism might be a promising target for SD-mediated AF susceptibility.

Serum and Urine Metabolites in Healthy Men after Consumption of Acidified Milk and Yogurt

The identification of molecular biomarkers that can be used to quantitatively link dietary intake to phenotypic traits in humans is a key theme in modern nutritional research. Although dairy products (with and without fermentation) represent a major food group, the identification of markers of their intake lags behind that of other food groups. Here, we report the results from an analysis of the metabolites in postprandial serum and urine samples from a randomized crossover study with 14 healthy men who ingested acidified milk, yogurt, and a non-dairy meal. Our study confirms the potential of lactose and its metabolites as markers of lactose-containing dairy foods and the dependence of their combined profiles on the fermentation status of the consumed products. Furthermore, indole-3-lactic acid and 3-phenyllactic acid are two products of fermentation whose postprandial behaviour strongly discriminates yogurt from milk intake. Our study also provides evidence of the ability of milk fermentation to increase the acute delivery of free amino acids to humans. Notably, 3,5-dimethyloctan-2-one also proves to be a specific marker for milk and yogurt consumption, as well as for cheese consumption (previously published data). These molecules deserve future characterisation in human interventional and observational studies.

Paroxetine effects in adult male rat colon: Focus on gut steroidogenesis and microbiota

Paroxetine, a selective serotonin reuptake inhibitor (SSRI), is prescribed to treat psychiatric disorders, although an off-label SSRI use is also for functional gastrointestinal disorders. The mutual correlation between serotonin and peripheral sex steroids has been reported, however little attention to sex steroids synthesized by gut, has been given so far. Indeed, whether SSRIs, may also influence the gut steroid production, immediately after treatment and/or after suspension, is still unclear. The finding that gut possesses steroidogenic capability is of particular relevance, also for the existence of the gut-microbiota-brain axis, where gut microbiota represents a key orchestrator. On this basis, adult male rats were treated daily for two weeks with paroxetine or vehicle and, 24 h after treatment and at 1 month of withdrawal, steroid environment and gut microbiota were evaluated. Results obtained reveal that paroxetine significantly affects steroid levels, only in the colon but not in plasma. In particular, steroid modifications observed immediately after treatment are not overlap with those detected at withdrawal. Additionally, paroxetine treatment and its withdrawal impact gut microbiota populations differently. Altogether, these results suggest a biphasic effect of the drug treatment in the gut both on steroidogenesis and microbiota.