Study of growth, metabolism, and morphology of Akkermansia muciniphila with an in vitro advanced bionic intestinal reactor

Development of fermented Atemoya (Annona cherimola × Annona squamosa)-Amazake increased intestinal next-generation probiotics

Akkermansia muciniphila and Faecalibacterium prausnitzii are next-generation probiotics, which has been reported to protect disease and effectively utilize various carbohydrates (starch and pectin) as nutrients for growth. Atemoya exhibiting fruity flavor, which is suitable for enhancing aroma and attenuating unpleasant taste caused by the koji metabolites. Results indicated that malic acid was increased (from 42.4 to 70.1 mg/100 g) in fermented Atemoya-Amazake. In addition, fermented Atemoya-Amazake elevated growthes in A. muciniphila and F. prausnitzii. Similarly, the populations of Parabacteroides (5.7 fold) and Akkermansia (1.66 fold) were elevated by fermented Atemoya-Amazake treatment in an in vitro simulated gastrointestinal system compared to the control group. Results revealed that fermented Atemoya-Amazake modulated the intestinal microbiota through increasing the production of short-chain fatty acids (exhibiting anti-pathogenic activity) for 2.1, 2.5, 2.6, and 2.1 folds in acetic acid, propionic acid, isobutyric acid, and butyric acid, respectively; suggesting this fermented Atemoya-Amazake could be applied in intestinal protection.

LC-HRMS-based metabolomics and lipidomics analyses of a novel probiotic Akkermansia Muciniphila in response to different nutritional stimulations

The mucin-degrading gut commensal Akkermansia muciniphila (A. muciniphila) negatively correlates with various diseases, including metabolic disorders, neurodegenerative disorders, and cancers, through interacting with host receptors by diverse molecules. Still, their exact metabolic capability within the nutrient-rich environment (such as in the human gut) is not fully characterized. Therefore, in the present study, we investigated the comprehensive metabolome and lipidome of A. muciniphila after supplementation of four major gut microbial nutrients: mucin, inorganic salts, bile salts, and short-chain fatty acids (SCFAs). Our results showed that mucin is the predominant driver of the different lipidomic and metabolomic profiles of A. muciniphila, and it promotes the overall growth of this bacteria. While the addition of inorganic salts, bile salts, and SCFAs was found to inhibit the growth of A. muciniphila. Interestingly, inorganic salts affected the purine metabolism in A. muciniphila cultures, while adding bile salts significantly increased the production of other bile acids and N-acyl amides. Lastly, SCFAs were identified to alter the A. muciniphila energy utilization of triglycerides, fatty acyls, and phosphatidylethanolamines. To our knowledge, this is the first study to examine the comprehensive lipidome and metabolome of A. muciniphila, which highlights the importance of nutritional impacts on the lipidome and metabolome of A. muciniphila and hence providing foundational knowledge to unveil the potential effects of A. muciniphila on host health.

Unveiling the immunomodulatory effect of the novel probiotic Akkermansia muciniphila and its protective effect in vitro

Akkermansia muciniphila, a bacterium found in the human microbiota, has gained interest due to its potential health benefits. Previous studies have linked its absence to inflammatory disorders, while also suggesting its role in maintaining a healthy gut barrier. However, there is limited information on its specific effects on the immune system. Therefore, the aim of this research was to analyze the in vitro response triggered by A. muciniphila employing RAW 264.7 macrophages. The study focused on investigating the production of cytokines and nitric oxide, along with evaluating the expression of inflammatory surface cellular markers. Additionally, we assessed its potential to protect against intestinal infections, using Salmonella enterica serovar Enteritidis as a model. Our findings reveal a modulation effect of A. muciniphila with pro-inflammatory features, including the release of pro-inflammatory cytokines and upregulation of CD40 and CD80 surface markers, in contrast with previous reported data. Importantly, A. muciniphila could protect against Salmonella infection by promoting macrophage activation, appearing as a promising probiotic candidate for the control of intestinal infections.

Next generation probiotics: Engineering live biotherapeutics

The population dynamics of the human microbiome have been associated with inflammatory bowel disease, cancer, obesity, autoimmune diseases, and many other human disease states. An emerging paradigm in treatment is the administration of live engineered organisms, also called next-generation probiotics. However, the efficacy of these microbial therapies can be limited by the organism's overall performance in the harsh and nutrient-limited environment of the gut. In this review, we summarize the current state of the art use of bacterial and yeast strains as probiotics, highlight the recent development of genetic tools for engineering new therapeutic functions in these organisms, and report on the latest therapeutic applications of engineered probiotics, including recent clinical trials. We also discuss the supplementation of prebiotics as a method of manipulating the microbiome and improving the overall performance of engineered live biotherapeutics.

The Effect of Clostridium butyricum on Gut Microbial Changes and Functional Profiles of Metabolism in High-fat Diet-fed Rats Depending on Age and Sex

Background/Aims

A high-fat diet (HFD) causes dysbiosis and promotes inflammatory responses in the colon. This study aims to evaluate the effects of Clostridium butyricum on HFD-induced gut microbial changes in rats.

Methods

Six-week-old Fischer-344 rats with both sexes were given a control or HFD during 8 weeks, and 1-to-100-fold diluted Clostridium butyricum were administered by gavage. Fecal microbiota analyses were conducted using 16S ribosomal RNA metagenomic sequencing and predictive functional profiling of microbial communities in metabolism.

Results

A significant increase in Ruminococcaceae and Lachnospiraceae, which are butyric acid-producing bacterial families, was observed in the probiotics groups depending on sex. In contrast, Akkermansia muciniphila, which increased through a HFD regardless of sex, and decreased in the probiotics groups. A. muciniphila positively correlated with Claudin-1 expression in males (P < 0.001) and negatively correlated with the expression of Claudin-2 (P = 0.042), IL-1β (P = 0.037), and IL-6 (P = 0.044) in females. In terms of functional analyses, a HFD decreased the relative abundances of M00131 (carbohydrate metabolism module), M00579, and M00608 (energy metabolism), and increased those of M00307 (carbohydrate metabolism), regardless of sex. However, these changes recovered especially in male C. butyricum groups. Furthermore, M00131, M00579, and M00608 showed a positive correlation and M00307 showed a negative correlation with the relative abundance of A. muciniphila (P < 0.001).

Conclusion

The beneficial effects of C. butyricum on HFD-induced gut dysbiosis in young male rats originate from the functional profiles of carbohydrate and energy metabolism.

Advances in Culturomics Research on the Human Gut Microbiome: Optimizing Medium Composition and Culture Techniques for Enhanced Microbial Discovery

Despite considerable advancements achieved using next-generation sequencing technologies in exploring microbial diversity, several species of the gut microbiome remain unknown. In this transformative era, culturomics has risen to prominence as a pivotal approach in unveiling realms of microbial diversity that were previously deemed inaccessible. Utilizing innovative strategies to optimize growth and culture medium composition, scientists have successfully cultured hard-to-cultivate microbes. This progress has fostered the discovery and understanding of elusive microbial entities, highlighting their essential role in human health and disease paradigms. In this review, we emphasize the importance of culturomics research on the gut microbiome and provide new theories and insights for expanding microbial diversity via the optimization of cultivation conditions.

Development of non-alcoholic steatohepatitis is associated with gut microbiota but not with oxysterol enzymes CH25H, EBI2, or CYP7B1 in mice

Liver steatosis is the most frequent liver disorder and its advanced stage, non-alcoholic steatohepatitis (NASH), will soon become the main reason for liver fibrosis and cirrhosis. The "multiple hits hypothesis" suggests that progression from simple steatosis to NASH is triggered by multiple factors including the gut microbiota composition. The Epstein Barr virus induced gene 2 (EBI2) is a receptor for the oxysterol 7a, 25-dihydroxycholesterol synthesized by the enzymes CH25H and CYP7B1. EBI2 and its ligand control activation of immune cells in secondary lymphoid organs and the gut. Here we show a concurrent study of the microbial dysregulation and perturbation of the EBI2 axis in a mice model of NASH.We used mice with wildtype, or littermates with CH25H-/-, EBI2-/-, or CYP7B1-/- genotypes fed with a high-fat diet (HFD) containing high amounts of fat, cholesterol, and fructose for 20 weeks to induce liver steatosis and NASH. Fecal and small intestinal microbiota samples were collected, and microbiota signatures were compared according to genotype and NASH disease state.We found pronounced differences in microbiota composition of mice with HFD developing NASH compared to mice did not developing NASH. In mice with NASH, we identified significantly increased 33 taxa mainly belonging to the Clostridiales order and/ or the family, and significantly decreased 17 taxa. Using an Elastic Net algorithm, we suggest a microbiota signature that predicts NASH in animals with a HFD from the microbiota composition with moderate accuracy (area under the receiver operator characteristics curve = 0.64). In contrast, no microbiota differences regarding the studied genotypes (wildtype vs knock-out CH25H-/-, EBI2-/-, or CYP7B1-/-) were observed.In conclusion, our data confirm previous studies identifying the intestinal microbiota composition as a relevant marker for NASH pathogenesis. Further, no link of the EBI2 - oxysterol axis to the intestinal microbiota was detectable in the current study.

Acute gastrointestinal permeability after traumatic brain injury in mice precedes a bloom in Akkermansia muciniphila supported by intestinal hypoxia

Traumatic brain injury (TBI) increases gastrointestinal morbidity and associated mortality. Clinical and preclinical studies implicate gut dysbiosis as a consequence of TBI and an amplifier of brain damage. However, little is known about the association of gut dysbiosis with structural and functional changes of the gastrointestinal tract after an isolated TBI. To assess gastrointestinal dysfunction, mice received a controlled cortical impact or sham brain injury and intestinal permeability was assessed at 4 h, 8 h, 1 d, and 3 d after injury by oral administration of 4 kDa FITC Dextran prior to euthanasia. Quantification of serum fluorescence revealed an acute, short-lived increase in permeability 4 h after TBI. Despite transient intestinal dysfunction, no overt morphological changes were evident in the ileum or colon across timepoints from 4 h to 4 wks post-injury. To elucidate the timeline of microbiome changes after TBI, 16 s gene sequencing was performed on DNA extracted from fecal samples collected prior to and over the first month after TBI. Differential abundance analysis revealed that the phylum Verrucomicrobiota was increased at 1, 2, and 3 d after TBI. The Verrucomicrobiota species was identified by qPCR as Akkermansia muciniphila, an obligate anaerobe that resides in the intestinal mucus bilayer and produces short chain fatty acids (e.g. butyrate) utilized by intestinal epithelial cells. We postulated that TBI promotes intestinal changes favorable for the bloom of A. muciniphila. Consistent with this premise, the relative area of mucus-producing goblet cells in the medial colon was significantly increased at 1 d after injury, while colon hypoxia was significantly increased at 3 d. Our findings reveal acute gastrointestinal functional changes coupled with an increase of beneficial bacteria suggesting a potential compensatory response to systemic stress after TBI.

Akkermansia muciniphila-derived small extracellular vesicles attenuate intestinal ischemia-reperfusion-induced postoperative cognitive dysfunction by suppressing microglia activation via the TLR2/4 signaling

Akkermansia muciniphila (AKK) bacteria improve the functions of theere intestinal and blood-brain barriers (BBB) via their extracellular vesicles (AmEvs). However, their role in postoperative cognitive dysfunction (POCD) and its underlying mechanisms remain unclear. To investigate, we used C57BL/6 J mice divided into five groups: Sham, POCD, POCD+Akk, POCD+Evs, and POCD+Evs + PLX5622. POCD was induced through intestinal ischemia-reperfusion (I/R). The mice's cognitive function was assessed using behavioral tests, and possible mechanisms were explored by examining gut and BBB permeability, inflammation, and microglial function. Toll-like receptor (TLR) 2/4 pathway-related proteins were also investigated both in vitro and in vivo. PLX5622 chow was employed to eliminate microglial cells. Our findings revealed a negative correlation between AKK abundance and POCD symptoms. Supplementation with either AKK or AmEvs improved cognitive function, improved the performance of the intestinal barrier and BBB, and decreased inflammation and microglial activation in POCD mice compared to controls. Moreover, AmEvs treatment inhibited TLR2/4 signaling in the brains of POCD mice and LPS-treated microglial cells. In microglial-ablated POCD mice, however, AmEvs failed to protect BBB integrity. Overall, AmEvs is a potential therapeutic strategy for managing POCD by enhancing gut and BBB integrity and inhibiting microglial-mediated TLR2/4 signaling.

Akkermansia muciniphila and Alcohol-Related Liver Diseases. A Systematic Review

SCOPE

Akkermansia muciniphila (A. muciniphila) are Gram negative commensal bacteria, degrading mucin in the intestinal mucosa, modulating intestinal permeability and inflammation in the digestive tract, liver, and blood. Some components can promote the relative abundance of A. muciniphila in the gut microbiota, but lower levels of A. muciniphila are more commonly found in people with obesity, diabetes, metabolic syndromes, or inflammatory digestive diseases. Over-intake of ethanol can also induce a decrease of A. muciniphila, associated with dysregulation of microbial metabolite production, impaired intestinal permeability, induction of chronic inflammation, and production of cytokines.

METHODS AND RESULTS

Using a PRISMA search strategy, a review is performed on the bacteriological characteristics of A. muciniphila, the factors capable of modulating its relative abundance in the digestive tract and its probiotic use in alcohol-related liver diseases (alcoholic hepatitis, cirrhosis, hepatocellular carcinoma, hepatic transplantation, partial hepatectomy).

CONCLUSION

Several studies have shown that supplementation with A. muciniphila can improve ethanol-related hepatic pathologies, and highlight the interest in using this bacterial species as a probiotic.

Akkermansia muciniphila supplementation prevents cognitive impairment in sleep-deprived mice by modulating microglial engulfment of synapses

The microbiome-gut-brain axis plays a crucial role in many neurological diseases, including mild cognitive impairment. Sleep deprivation (SD) induces cognitive decline accompanied by alterations in the gut microbiota. However, the role of gut microbiota alterations in SD-induced cognitive dysfunction and the underlying mechanisms remain unclear. Here, we found that dysbiosis of the gut microbiota following pretreatment with broad-spectrum antibiotics worsens SD-induced cognitive impairment in mice. Fecal microbiota transplantation from SD mice to healthy mice induced cognitive impairment. Additionally, the abundance of Akkermansia muciniphila (A. muciniphila) in the mouse gut microbiota was significantly reduced after 7 days of SD. A. muciniphila pretreatment alleviated cognitive dysfunction and prevented synaptic reduction in the hippocampus in SD mice. A. muciniphila pretreatment inhibited extensive microglial activation and synaptic engulfment in the hippocampus of SD mice. Metabolomics analysis revealed that A. muciniphila pretreatment increased the serum acetate and butanoic acid levels in SD mice. Finally, pretreatment with short-chain fatty acids (SCFAs) inhibited microglial synaptic engulfment and prevented neuronal synaptic loss in SD mice and primary microglia-neuron co-culture following LPS stimulation. Together, our findings illustrate that gut dysbiosis plays an essential role in SD-induced cognitive impairment by activating microglial engulfment at synapses. A. muciniphila supplementation may be a novel preventative strategy for SD-induced cognitive dysfunction, by increasing SCFAs production and maintaining microglial homeostasis.

Strontium ranelate enriched Ruminococcus albus in the gut microbiome of Sprague-Dawley rats with postmenopausal osteoporosis

BACKGROUND

Gut microbiome is critical to our human health and is related to postmenopausal osteoporosis (PMO). Strontium ranelate (SrR) is an anti-osteoporosis oral drug that can promote osteoblast formation and inhibit osteoclast formation. However, the effect of SrR on gut microbiome has been rarely studied. Therefore, we investigated the effect of oral SrR on gut microbiome and metabolic profiles.

RESULTS

In this study, we used ovariectomized (OVX) Sprague-Dawley rats to construct a PMO model and applied oral SrR for 6 weeks. The relative abundance of intestinal microbiome was investigated by 16S rRNA metagenomic sequencing. Ultra-high-performance liquid chromatography-mass spectrometry (UHPLC-MS) was used to analyze changes in metabolites of intestinal contents. Results demonstrated that 6-week oral SrR alleviated osteoporosis and significantly changed the composition of the gut microbiome and metabolic profiles of OVX rats. Ruminococcus, Akkermansia and Oscillospira were significantly enriched in the gut of OVX rats after 6-week oral SrR. Especially, the species R. albus showed the greatest importance by a random forest classifier between OVX and OVX_Sr group. The enrichment of R. albus in the gut was positively correlated with bone mineral density and the accumulation of lycopene and glutaric acid, which also significantly elevated after oral SrR.

CONCLUSIONS

We discovered that oral SrR can improve bone health while stimulate the accumulation of gut microbe R. albus and metabolites (lycopene and glutaric acid). The results suggested possible connections between oral SrR and the gut-bone axis, which may provide new insight into the treatment/prevention of osteoporosis.

Interaction between Akkermansia muciniphila and Diet Is Associated with Proinflammatory Index in School-Aged Children

BACKGROUND

Imbalance in the intestinal microbiota can lead to chronic low-grade inflammation. Diet may influence this association. In this study, we aimed to evaluate the interaction between Akkermansia muciniphila (A. muciniphila) and dietary patterns using a proinflammatory index.

METHODS

We conducted a cross-sectional study with school-aged children. We quantified the relative abundance (RA) of A. muciniphila in feces using a polymerase chain reaction. We collected dietary information through employing a food frequency questionnaire and generated dietary patterns using principal component analysis. We generated a proinflammatory index from serum levels of interleukin-6, interleukin-10, tumor necrosis factor alpha, and adiponectin validated by receptor operating characteristic curves. We evaluated the association between A. muciniphila and the proinflammatory index using logistic regression, including an interaction term with dietary patterns.

RESULTS

We found that children with a low RA of A. muciniphila and a high intake of simple carbohydrates and saturated fats had increased odds of being high on the proinflammatory index. However, when the consumption of this dietary pattern is low, children with a low RA of A. muciniphila had decreased odds of being high on the proinflammatory index.

CONCLUSIONS

Our results suggest that the simultaneous presence of A. muciniphila and diet have a more significant impact on the presence of being high on the proinflammatory index compared to both factors separately.

The Immunomodulatory Effect of β-Glucan Depends on the Composition of the Gut Microbiota

This study aimed to elucidate the relationship between the immunomodulatory effects of β-glucan and the composition of gut microbiota in mice. The mice were fed a diet containing β-glucan for 3 weeks, and feces, blood, and tissues were then collected to analyze the immunomodulatory effect and gut microbiota composition. Based on the results of the analysis of the expression level of immune-associated proteins, the high immunomodulatory effect group (HIE) and low immunomodulatory effect group (LIE) were categorized. Before the β-glucan diet, the proportions of the phylum Bacteroidota, family Muribaculaceae, and family Lactobacillaceae were significantly higher in HIE than in LIE. Furthermore, the genus Akkermansia was absent before the β-glucan diet and increased after β-glucan diet. These microbes had the ability to metabolize β-glucan or were beneficial to health. In conclusion, our findings demonstrate that variation in the composition of gut microbiota among individuals can result in varying expressions of β-glucan functionality. This outcome supports the notion that β-glucan may be metabolized through diverse pathways by gut microbes originally possessed by mice, subsequently producing various metabolites, such as short-chain fatty acids. Alternatively, the viscosity of the intestinal mucosa could be enhanced by β-glucan, potentially promoting the growth of certain bacteria (e.g., the genus Akkermansia). This study provides insights into the intricate interplay between β-glucan, gut microbiota, and immunomodulation.

Microbiome distribution modeling using gradient descent strategies for mock, in vitro and clinical community distributions

The human gut is home to a complex array of microorganisms interacting with the host and each other, forming a community known as the microbiome. This community has been linked to human health and disease, but understanding the underlying interactions is still challenging for researchers. Standard studies typically use high-throughput sequencing to analyze microbiome distribution in patient samples. Recent advancements in meta-omic data analysis have enabled computational modeling strategies to integrate this information into an in silico model. However, there is a need for improved parameter fitting and data integration features in microbial community modeling. This study proposes a novel alternative strategy utilizing state-of-the-art dynamic flux balance analysis (dFBA) to provide a simple protocol enabling accurate replication of abundance data composition through dynamic parameter estimation and integration of metagenomic data. We used a recurrent optimization algorithm to replicate community distributions from three different sources: mock, in vitro, and clinical microbiome. Our results show an accuracy of 98% and 96% when using in vitro and clinical bacterial abundance distributions, respectively. The proposed modeling scheme allowed us to observe the evolution of metabolites. It could provide a deeper understanding of metabolic interactions while taking advantage of the high contextualization features of GEM schemes to fit the study case. The proposed modeling scheme could improve the approach in cases where external factors determine specific bacterial distributions, such as drug intake.

Development of an In Vitro Model of the Gut Microbiota Enriched in Mucus-Adhering Bacteria

Culturing the gut microbiota in in vitro models that mimic the intestinal environment is increasingly becoming a promising alternative approach to study microbial dynamics and the effect of perturbations on the gut community. Since the mucus-associated microbial populations in the human intestine differ in composition and functions from their luminal counterpart, we attempted to reproduce in vitro the microbial consortia adhering to mucus using an already established three-dimensional model of the human gut microbiota. Electrospun gelatin structures supplemented or not with mucins were inoculated with fecal samples and compared for their ability to support microbial adhesion and growth over time, as well as to shape the composition of the colonizing communities. Both scaffolds allowed the establishment of long-term stable biofilms with comparable total bacterial loads and biodiversity. However, mucin-coated structures harbored microbial consortia especially enriched in Akkermansia, Lactobacillus, and Faecalibacterium, being therefore able to select for microorganisms commonly considered mucosa-associated in vivo. IMPORTANCE These findings highlight the importance of mucins in shaping intestinal microbial communities, even those in artificial gut microbiota systems. We propose our in vitro model based on mucin-coated electrospun gelatin structures as a valid device for studies evaluating the effects of exogenous factors (nutrients, probiotics, infectious agents, and drugs) on mucus-adhering microbial communities.

The balanced unsaturated fatty acid supplement constituted by woody edible oils improved lipid metabolism and gut microbiota in high-fat diet mice

The dietary intervention has demonstrated effectiveness in improving hyperlipidemia and obesity. Woody edible oils are rich in unsaturated fatty acids (UFAs) that could positively affect lipid metabolism. In this study, the blended oil (BLO), a balanced UFA supplement, constituted by Zanthoxylum bungeanum (Chinese Red Pepper) seed oil, walnut (Juglans regia) oil, camellia (Camema oleifera) seed oil and perilla (Perilla frutescens) seed oil was established referring to the Chinese dietary reference intakes, in which the ratios of monounsaturated/polyunsaturated fatty acids and ω-6/ω-3 polyunsaturated fatty acids were 1:1 and 4:1, respectively. The BLO was administrated to KM mice fed a high-fat diet (HFD) by gavage every day at a dose of 3.0 mL/kg·bw for 10 weeks to assess its effects on serum lipid levels, liver antioxidant activities and gut microbial composition. The results showed that the BLO improved hepatic steatosis, liver oxidative stress, and serum lipid levels. Additionally, there was an increased abundance of Lactobacillus, Allobaculum, and Blautia, along with a decreased abundance of Staphylococcus in cecal contents. These changes were found to be positively correlated with the metabolic improvements, as indicated by Spearman's correlation analysis. These findings implied the practicality of the balanced unsaturated fatty acid consumption in preventing hyperlipidemia and obesity.

Effect of polysaccharide derived from dehulled adlay on regulating gut microbiota and inhibiting Clostridioides difficile in an in vitro colonic fermentation model

Human body can digest only a few sugars with a low degree of polymerization. The rest of the carbohydrates become food for gastrointestinal symbiotic bacteria, affecting gut microbiota composition and human health. Adlay is a medicinal and food homologous crop. The study aims to determine whether dehulled adlay-derived polysaccharide regulates gut microbiota and barrier function to against Clostridioides difficile infection. Major molecular weight of adlay polysaccharide is 27 kDa. The growth of next-generation probiotics were promoted by adlay polysaccharides. In colonic fermentation model, the ratio of C. difficile was decreased when adding the condition medium of adlay polysaccharides-treated fecal microbiota. In addition, adlay polysaccharide promoted the expression of tight junction proteins and mucin in intestinal cells. This study shows that adlay polysaccharide can be used as prebiotics to regulate microbiota and maintain barrier function, which has the potential to be developed as novel functional food ingredients to protect intestinal health.

Akkermansia muciniphila exerts immunomodulatory and anti-inflammatory effects on gliadin-stimulated THP-1 derived macrophages

Macrophages (MQs) pro-inflammatory phenotype is triggered by gliadin peptides. Akkermansia muciniphila (A. muciniphila) showed to enhance the anti-inflammatory phenotype of MQs. This study aimed to investigate the anti-inflammatory effects of A. muciniphila, on gliadin stimulated THP-1 derived macrophages. THP-1 cell line monocytes were differentiated into MQs by phorbol 12-myristate 13-acetate (PMA). MQs were treated with A. muciniphila before and after stimulation with gliadin (pre- and post-treat). CD11b, as a marker of macrophage differentiation, and CD206 and CD80, as M1 and M2 markers, were evaluated by flow cytometry technique. The mRNA expression of TGF-β, IL-6, and IL-10 and protein levels of IL-10 and TNF-α were measured by RT-PCR and ELISA techniques, respectively. Results show an increased percentage of M1 phenotype and release of proinflammatory cytokines (like TNF-α and IL-6) by macrophages upon incubation with gliadin. Pre- and post-treatment of gliadin-stimulated macrophages with A. muciniphila induced M2 phenotype associated with decreased proinflammatory (IL-6, TNF-α) and increased anti-inflammatory (IL-10, TGF-β) cytokines expression relative to the group that was treated with gliadin alone. This study suggests the potential beneficial effect of A. muciniphila on gliadin-stimulated MQs and the importance of future studies focusing on their exact mechanism of action on these cells.

Lacto-Fermented and Unfermented Soybean Differently Modulate Serum Lipids, Blood Pressure and Gut Microbiota during Hypertension

Soy consumption may reduce hypertension but the impact of food processing on the antihypertensive effect is unclear. Hence, we ascertained the effects of lacto-fermented (FSB) and unfermented soybean (USB) consumption on serum atherogenic lipids, hypertension and gut microbiota of spontaneous hypertensive rats (SHR). FSB displayed a strong in vitro angiotensin converting enzyme (ACE) inhibitory ability of 70 ± 5% while USB inhibited 5 ± 3% of the enzyme activity. Consumption of USB reduced serum ACE activity by 19.8 ± 12.85 U while FSB reduced the enzyme activity by 47.6 ± 11.35 U, respectively. FSB significantly improved cholesterol levels and reduced systolic and diastolic blood pressures by 14 ± 3 mmHg and 10 ± 3 mmHg, respectively, while USB only had a marginal impact on blood pressure. Analysis of FSB showed the abundance of ACE inhibitory peptides EGEQPRPFPFP and AIPVNKP (which were absent in USB) and 30 phenolic compounds (only 12 were abundant in USB). Feeding SHR with FSB promoted the growth of Akkermansia, Bacteroides, Intestinimonas, Phocaeicola, Lactobacillus and Prevotella (short chain fatty acid producers) while USB promoted only Prevotellamassilia, Prevotella and Intestimonas levels signifying the prebiotic ability of FSB. Our results show that, relative to USB, FSB are richer in bioactive compounds that reduce hypertension by inhibiting ACE, improving cholesterol levels and mitigating gut dysbiosis.

Indispensable role of melatonin, a scavenger of reactive oxygen species (ROS), in the protective effect of Akkermansia muciniphila in cadmium-induced intestinal mucosal damage

The gastrointestinal tract is the main target of cadmium toxicity. However, whether Akkermansia muciniphila (A. muciniphila), which has been reported to be the next generation of promising probiotics, can alleviate cadmium-induced intestinal damage has not been investigated. In this study, we found that compared to the cadmium exposure group, mice gavaged with A. muciniphila showed less severe intestinal mucosal damage, with improved bodyweight, colon length, a decline in inflammation, and significantly increased glutathione and goblet cell numbers. Meanwhile, melatonin was interestingly found to be strikingly increased after A. muciniphila treatment. We then demonstrated that melatonin also could ameliorate the intestinal mucosal damage caused by cadmium through scavenging reactive oxygen species (ROS) and increasing the number of goblet cells. Furthermore, mice treated with inhibitors had a low level of melatonin and could not reproduce the beneficial effects of the A. muciniphila. Our results implied that the regulation of melatonin production by A. muciniphila is associated with an increase in enterochromaffin cells number, which determine melatonin secretion. This study indicated that the A. muciniphila-melatonin axis reduces cadmium-induced damage by increasing the goblet cells and scavenging the ROS, which may guide the prevention of the toxic effects of heavy metals.

The effects of high-fat foods on gut microbiota and small molecule intestinal gases: release kinetics and distribution in vitro colon model

Profiling intestinal gases and their responses to dietary changes can reveal the products and functions of the gut microbiota and their influence on human health. High-fat foods (HFF) can alter the gut microbiota and its metabolites, posing a potential health risk. However, little is known about the effects of HFF on intestinal gas distribution. Therefore, in this study, we used human fecal microorganisms as strains, an in vitro three-chamber colon model and an intestinal gas array sensor as tools. We performed in vitro fermentation using HFF as the fermentation substrate to reveal the effects of HFF on the kinetics of intestinal gas production and changes in the gut microbiota and its metabolites. We found that dietary fatty acids stimulated the production of H2S and volatile organic compounds in the colon, promoted Firmicutes abundance, and decreased Bacteroidetes abundance. These results highlight the potential role of HFF in altering the gut microbiota and intestinal gas, which can lead to health hazards.

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High-fat foods (HFF) can alter the gut microbiota and its metabolites.

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HFF stimulate H₂S and volatile organic compound production in the colon.

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Specific intestinal gases can be used as disease markers.

Olanzapine-induced lipid disturbances: A potential mechanism through the gut microbiota-brain axis

Objective: Long-term use of olanzapine can induce various side effects such as lipid metabolic disorders, but the mechanism remains to be elucidated. The gut microbiota-brain axis plays an important role in lipid metabolism, and may be related to the metabolic side effects of olanzapine. Therefore, we explored the mechanism by which olanzapine-induced lipid disturbances through the gut microbiota-brain axis.

Methods: Sprague Dawley rats were randomly divided into two groups, which underwent subphrenic vagotomy and sham surgery. Then the two groups were further randomly divided into two subgroups, one was administered olanzapine (10 mg/kg/day) by intragastric administration, and the other was administered normal saline by intragastric administration (4 ml/kg/day) for 2 weeks. The final changes in lipid parameters, gut microbes and their metabolites, and orexin-related neuropeptides in the hypothalamus were investigated among the different groups.

Results: Olanzapine induced lipid disturbances as indicated by increased weight gain, elevated ratio of white adipose tissue to brown adipose tissue, as well as increased triglyceride and total cholesterol. Olanzapine also increased the Firmicutes/Bacteroides (F/B) ratio in the gut, which was even aggravated by subphrenic vagotomy. In addition, olanzapine reduced the abundance of short-chain fatty acids (SCFAs) metabolism related microbiome and 5-hydroxytryptamine (5-HT) levels in the rat cecum, and increased the gene and protein expression of the appetite-related neuropeptide Y/agouti-related peptide (NPY/AgRP) in the hypothalamus.

Conclusion: The abnormal lipid metabolism caused by olanzapine may be closely related to the vagus nerve-mediated gut microbiota-brain axis.

Production of prebiotic gellan oligosaccharides based on the irradiation treatment and acid hydrolysis of gellan gum

Biologically active gellan oligosaccharides (GOSs), newly found plant elicitors and biostimulants, are produced from the hydrolysis of gellan gum. Traditional hydrolysis with concentrated acid suffers from the problems of high pollution and low functional oligosaccharide yield because the process is difficult to control. Irradiation (⁶⁰Co γ-ray) with a dosage ranging from 0 kGy to 175 kGy was used to degrade gellan gum efficiently and cleanly into low molecular weight (M_w) gellan with an average M_w ranging from 449,119 Da to 72,903 Da. The low M_w gellan irradiated at 70 kGy was further hydrolyzed with low concentration acid (0.5 mol/L HCl) to produce GOSs with DPs mainly 4 and 8, indicating that the Rha-β-(1 → 3)-Glc bonds in gellan gum were easily cut to produce residues with tetrasaccharide repeat subunits. Besides antioxidant activity, GOSs were also proved with prebiotic activity by in vitro fecal fermentation in a self-designed bionic intestinal reactor.

Selection strategy of dextran sulfate sodium-induced acute or chronic colitis mouse models based on gut microbial profile

BACKGROUND

Dextran sulfate sodium (DSS) replicates ulcerative colitis (UC)-like colitis in murine models. However, the microbial characteristics of DSS-triggered colitis require further clarification. To analyze the changes in gut microbiota associated with DSS-induced acute and chronic colitis.

METHODS

Acute colitis was induced in mice by administering 3% DSS for 1 week in the drinking water, and chronic colitis was induced by supplementing drinking water with 2.5% DSS every other week for 5 weeks. Control groups received the same drinking water without DSS supplementation. The histopathological score and length of the colons, and disease activity index (DAI) were evaluated to confirm the presence of experimental colitis. Intestinal microbiota was profiled by 16S rDNA sequencing of cecal content.

RESULTS

Mice with both acute and chronic DSS-triggered colitis had significantly higher DAI and colon histopathological scores in contrast to the control groups (P < 0.0001, P < 0.0001), and the colon was remarkably shortened (P < 0.0001, P < 0.0001). The gut microbiota α-diversity was partly downregulated in both acute and chronic colitis groups in contrast to their respective control groups (Pielou index P = 0.0022, P = 0.0649; Shannon index P = 0.0022, P = 0.0931). The reduction in the Pielou and Shannon indices were more obvious in mice with acute colitis (P = 0.0022, P = 0.0043). The relative abundance of Bacteroides and Turicibacter was increased (all P < 0.05), while that of Lachnospiraceae, Ruminococcaceae, Ruminiclostridium, Rikenella, Alistipes, Alloprevotella, and Butyricicoccus was significantly decreased after acute DSS induction (all P < 0.05). The relative abundance of Bacteroides, Akkermansia, Helicobacter, Parabacteroides, Erysipelatoclostridium, Turicibacter and Romboutsia was also markedly increased (all P < 0.05), and that of Lachnospiraceae_NK4A136_group, Alistipes, Enterorhabdus, Prevotellaceae_UCG-001, Butyricicoccus, Ruminiclostridium_6, Muribaculum, Ruminococcaceae_NK4A214_group, Family_XIII_UCG-001 and Flavonifractor was significantly decreased after chronic DSS induction (all P < 0.05).

CONCLUSION

DSS-induced acute and chronic colitis demonstrated similar symptoms and histopathological changes. The changes in the gut microbiota of the acute colitis model were closer to that observed in UC. The acute colitis model had greater abundance of SCFAs-producing bacteria and lower α-diversity compared to the chronic colitis model.

In vitro digestion and fecal fermentation of highly resistant starch rice and its effect on the gut microbiota

Highly resistant starch rice (HRSR) is of particular interest in terms of its capacity to deliver short-chain fatty acids (SCFAs) to the colon in the prevention of diabetes mellitus and obesity. In this study, HRSR was processed into cooked rice, rice milk, rice cake, and rice popcorn, and the in vitro digestion and fermentation processes were monitored. The results showed that the starch digestibility of the four samples conformed to a first-order two-phase equation, and the resistant starch content of rice cake was the highest (11.98%). Compared with inulin, rice cake had a slower fermentation rate, and the butyrate concentration increased by 67.85%. The abundances of Prevotellaceae, which promotes the synthesis of SCFAs, and anti-inflammatory Faecalibacterium increased. The abundances of Proteobacteria and Megamonas, markers of gut microbiota imbalance, decreased. The results might facilitate the design and production of functional food products for type 2 diabetic and obese patients and improving colonic health.