Modulation of the immune response and metabolism in germ-free rats colonized by the probiotic Lactobacillus salivarius LI01

Microbiota-related metabolites correlated with the severity of COVID-19 patients

BACKGROUND

Coronavirus disease 2019 (COVID-19) is a global pandemic with high mortality, and the treatment options for the severe patients remain limited. Previous studies reported the altered gut microbiota in severe COVID-19. But there are no comprehensive data on the role of microbial metabolites in COVID-19 patients.

METHODS

We identified 153 serum microbial metabolites and assessed the changes in 72 COVID-19 patients upon admission and one-month after their discharge, comparing these changes to those in 133 healthy control individuals from the outpatient department during the same period.

RESULTS

Our study revealed that microbial metabolites varied across different stages and severity of COVID-19 patients. These altered microbial metabolites included tryptophan, bile acids, fatty acids, amino acids, vitamins and those containing benzene. A total of 13 distinct microbial metabolites were identified in COVID-19 patients compared to healthy controls. Notably, correlations were found among these disrupted metabolites and organ injury and inflammatory responses related to COVID-19. Furthermore, these metabolites did not restore to the normal levels one month after discharge. Importantly, two microbial metabolites were the core microbial metabolites related to the severity of COVID-19 patients.

CONCLUSIONS

The microbial metabolites were altered in the acute and recovery stage, correlating with disease severity of COVID-19. These results indicated the important role of gut microbiota in the progression of COVID-19, and facilitated the potential therapeutic microbial target for severe COVID-19 patients.

Buqi-Huoxue-Tongnao decoction drives gut microbiota-derived indole lactic acid to attenuate ischemic stroke via the gut-brain axis

BACKGROUND

Ischemic stroke belongs to "apoplexy" and its pathogenesis is characterized by qi deficiency and blood stasis combining with phlegm-damp clouding orifices. Buqi-Huoxue-Tongnao decoction (BHTD) is a traditional Chinese medicine formula for qi deficiency, blood stasis and phlegm obstruction syndrome. However, its efficacy and potential mechanism on ischemic stroke are still unclear. This study aims to investigate the protective effect and potential mechanism of BHTD against ischemic stroke.

MATERIALS AND METHODS

Middle cerebral artery occlusion (MCAO) surgery was carried out to establish an ischemic stroke model in rats. Subsequently, the rats were gavaged with different doses of BHTD (2.59, 5.175, 10.35 g/kg) for 14 days. The protective effects of BHTD on the brain and gut were evaluated by neurological function scores, cerebral infarction area, levels of brain injury markers (S-100B, NGB), indicators of gut permeability (FD-4) and bacterial translocation (DAO, LPS, D-lactate), and tight junction proteins (Occludin, Claudin-1, ZO-1) in brain and colon. 16S rRNA gene sequencing and metabolomic analysis were utilized to analyze the effects on gut microecology and screen for marker metabolites to explore potential mechanisms of BHTD protection against ischemic stroke.

RESULTS

BHTD could effectively mitigate brain impairment, including reducing neurological damage, decreasing cerebral infarction and repairing the blood-brain barrier, and BHTD showed the best effect at the dose of 10.35 g/kg. Moreover, BHTD reversed gut injury induced by ischemic stroke, as evidenced by decreased intestinal permeability, reduced intestinal bacterial translocation, and enhanced intestinal barrier integrity. In addition, BHTD rescued gut microbiota dysbiosis by increasing the abundance of beneficial bacteria, including Turicibacter and Faecalibaculum. Transplantation of the gut microbiota remodeled by BHTD into ischemic stroke rats recapitulated the protective effects of BHTD. Especially, BHTD upregulated tryptophan metabolism, which promoted gut microbiota to produce more indole lactic acid (ILA). Notably, supplementation with ILA by gavage could alleviate stroke injury, which suggested that driving the production of ILA in the gut might be a novel treatment for ischemic stroke.

CONCLUSION

BHTD could increase gut microbiota-derived indole lactic acid to attenuate ischemic stroke via the gut-brain axis. Our current finding provides evidence that traditional Chinese medicine can ameliorate central diseases through regulating the gut microbiology.

The arginine and nitric oxide metabolic pathway regulate the gut colonization and expansion of Ruminococcous gnavus

Ruminococcus gnavus is a mucolytic commensal bacterium whose increased gut colonization has been associated with chronic inflammatory and metabolic diseases in humans. Whether R. gnavus metabolites can modulate host intestinal physiology remains largely understudied. We performed untargeted metabolomic and bulk RNA-seq analyses using R. gnavus monocolonization in germ-free mice. Based on transcriptome-metabolome correlations, we tested the impact of specific arginine metabolites on intestinal epithelial production of nitric oxide (NO) and examined the effect of NO on the growth of various strains of R. gnavus in vitro and in nitric oxide synthase 2 (Nos2)-deficient mice. R. gnavus produces specific arginine, tryptophan, and tyrosine metabolites, some of which are regulated by the environmental richness of sialic acid and mucin. R. gnavus colonization promotes expression of amino acid transporters and enzymes involved in metabolic flux of arginine and associated metabolites into NO. R. gnavus induced elevated levels of NOS2, while Nos2 ablation resulted in R. gnavus expansion in vivo. The growth of various R. gnavus strains can be inhibited by NO. Specific R. gnavus metabolites modulate intestinal epithelial cell NOS2 abundance and reduce epithelial barrier function at higher concentrations. Intestinal colonization and interaction with R. gnavus are partially regulated by an arginine-NO metabolic pathway, whereby a balanced control by the gut epithelium may restrain R. gnavus growth in healthy individuals. Disruption in this arginine metabolic regulation will contribute to the expansion and blooming of R. gnavus.

Linking serotonin homeostasis to gut function: Nutrition, gut microbiota and beyond

Serotonin (5-HT) produced by enterochromaffin (EC) cells in the digestive tract is crucial for maintaining gut function and homeostasis. Nutritional and non-nutritional stimuli in the gut lumen can modulate the ability of EC cells to produce 5-HT in a temporal- and spatial-specific manner that toning gut physiology and immune response. Of particular interest, the interactions between dietary factors and the gut microbiota exert distinct impacts on gut 5-HT homeostasis and signaling in metabolism and the gut immune response. However, the underlying mechanisms need to be unraveled. This review aims to summarize and discuss the importance of gut 5-HT homeostasis and its regulation in maintaining gut metabolism and immune function in health and disease with special emphasis on different types of nutrients, dietary supplements, processing, and gut microbiota. Cutting-edge discoveries in this area will provide the basis for the development of new nutritional and pharmaceutical strategies for the prevention and treatment of serotonin homeostasis-related gut and systematic disorders and diseases.

Gut microbiota and serum metabolomic alterations in modulating the impact of fecal microbiota transplantation on ciprofloxacin-induced seizure susceptibility

Introduction

The gut microbiota and the microbiota-gut-brain axis have gained considerable attention in recent years, emerging as key players in the mechanisms that mediate the occurrence and progression of many central nervous system-related diseases, including epilepsy. In clinical practice, one of the side effects of quinolone antibiotics is a lower seizure threshold or aggravation. However, the underlying mechanism remains unclear.

Methods

We aimed to unravel the intrinsic mechanisms through 16S rRNA sequencing and serum untargeted metabolomic analysis to shed light on the effects of gut microbiota in ciprofloxacin-induced seizure susceptibility and lithium pilocarpine-induced epilepsy rat models.

Results

We observed that ciprofloxacin treatment increased seizure susceptibility and caused gut dysbiosis. We also found similar changes in the gut microbiota of rats with lithium pilocarpine-induced epilepsy. Notably, the levels of Akkermansia and Bacteroides significantly increased in both the ciprofloxacin-induced seizure susceptibility and lithium pilocarpine-induced epilepsy rat models. However, Marvinbryantia, Oscillibacter, and Ruminococcaceae_NK4A214_group showed a coincidental reduction. Additionally, the serum untargeted metabolomic analysis revealed decreased levels of indole-3-propionic acid, a product of tryptophan-indole metabolism, after ciprofloxacin treatment, similar to those in the plasma of lithium pilocarpine-induced epilepsy in rats. Importantly, alterations in the gut microbiota, seizure susceptibility, and indole-3-propionic acid levels can be restored by fecal microbiota transplantation.

Conclusion

In summary, our findings provide evidence that ciprofloxacin-induced seizure susceptibility is partially mediated by the gut microbiota and tryptophan-indole metabolism. These associations may play a role in epileptogenesis, and impacting the development progression and treatment outcomes of epilepsy.

Treatment and prevention of pigeon diarrhea through the application of Lactobacillus SNK-6

In the pigeon industry, treating and preventing diarrhea is vital because it is a serious health problem for pigeons. This study investigated the incidence of diarrhea in 3 pigeon farms in Shanghai, and analyzed the microflora through 16S rDNA high-throughput sequencing. Four strains of Escherichia coli (E. coli) isolated from pigeon diarrhea feces were administered via gavage to healthy pigeons, with each pigeon receiving 2 × 108 CFU. Pigeons that developed diarrhea after E. coli challenge were treated with 3 g of Lactobacillus salivarius SNK-6 (L. salivarius SNK-6) health sand (1.6 × 107 CFU/g). Then, a mass feeding experiment expanded to 688 pairs of pigeons with 3 replicates, each receiving 3 g of health sand containing L. salivarius SNK-6 (1.6 × 107 CFU/g) every 2 wk, and fecal status monitored and recorded. The study found that the relative abundance of the Lactobacillus genus and L. salivarius in feces from pigeons with diarrhea was significantly lower than in normal pigeon feces (P < 0.05). In contrast, E. coli showed a higher abundance and diversity in feces from pigeons with diarrhea than in normal feces (P < 0.05). Three out of the 4 isolated E. coli strains caused pigeon diarrhea, resulting in a significant reduction in microbial diversity in fecal samples (P < 0.05). Both the small group attack experiment and the mass-fed additive experiment in pigeon farms demonstrated that feeding L. salivarius SNK-6 effectively cured and prevented diarrhea. Pigeons fed with L. salivarius SNK-6 exhibited no diarrhea, while the control group had a 10% diarrhea rate. In summary, a deficiency of Lactobacillus or a high abundance of E. coli in the intestine could easily cause pigeon diarrhea. Feeding L. salivarius SNK-6 could treat pigeon diarrhea, and continuous supplementation could maintain stable preventive effects.

Biotics: An emerging food supplement for health improvement in the era of immune modulation

The involvement of the commensal microbiota in immune function is a multifold process. Biotics, such as probiotics, prebiotics, synbiotics, and paraprobiotics, have been subjected to animal and human trials demonstrating the association between gut microbes and immunity biomarkers leading to improvement in overall health. In recent years, studies on human microbiome interaction have established the multifarious role of biotics in maintaining overall health. The consumption of biotics has been extensively reported to help in maintaining microbial diversity, enhancing gut-associated mucosal immune homeostasis, and providing protection against a wide range of lifestyle disorders. However, the establishment of biotics as an alternative therapy for a range of health conditions is yet to be ascertained. Despite the fact that scientific literature has demonstrated the correlation between biotics and immune modulation, most in vivo and in vitro reports are inconclusive on the dosage required. This review provides valuable insights into the immunomodulatory effects of biotics consumption based on evidence obtained from animal models and clinical trials. Furthermore, we highlight the optimal dosages of biotics that have been reported to deliver maximum health benefits. By identifying critical research gaps, we have suggested a roadmap for future investigations to advance our understanding of the intricate crosstalk between biotics and immune homeostasis.

Novel Synergistic Probiotic Intervention: Transcriptomic and Metabolomic Analysis Reveals Ameliorative Effects on Immunity, Gut Barrier, and Metabolism of Mice during Salmonella typhimurium Infection

Salmonella typhimurium (S. typhimurium), a prevalent cause of foodborne infection, induces significant changes in the host transcriptome and metabolome. The lack of therapeutics with minimal or no side effects prompts the scientific community to explore alternative therapies. This study investigates the therapeutic potential of a probiotic mixture comprising Lactobacillus acidophilus (L. acidophilus 1.3251) and Lactobacillus plantarum (L. plantarum 9513) against S. typhimurium, utilizing transcriptome and metabolomic analyses, a novel approach that has not been previously documented. Twenty-four SPF-BALB/c mice were divided into four groups: control negative group (CNG); positive control group (CPG); probiotic-supplemented non-challenged group (LAPG); and probiotic-supplemented Salmonella-challenged group (LAPST). An RNA-sequencing analysis of small intestinal (ileum) tissue revealed 2907 upregulated and 394 downregulated DEGs in the LAPST vs. CPG group. A functional analysis of DEGs highlighted their significantly altered gene ontology (GO) terms related to metabolism, gut integrity, cellular development, and immunity (p ≤ 0.05). The KEGG analysis showed that differentially expressed genes (DEGs) in the LAPST group were primarily involved in pathways related to gut integrity, immunity, and metabolism, such as MAPK, PI3K-Akt, AMPK, the tryptophan metabolism, the glycine, serine, and threonine metabolism, ECM-receptor interaction, and others. Additionally, the fecal metabolic analysis identified 1215 upregulated and 305 downregulated metabolites in the LAPST vs. CPG group, implying their involvement in KEGG pathways including bile secretion, propanoate metabolism, arginine and proline metabolism, amino acid biosynthesis, and protein digestion and absorption, which are vital for maintaining barrier integrity, immunity, and metabolism. In conclusion, these findings suggest that the administration of a probiotic mixture improves immunity, maintains gut homeostasis and barrier integrity, and enhances metabolism in Salmonella infection.

Tryptophan, an important link in regulating the complex network of skin immunology response in atopic dermatitis

Atopic dermatitis (AD) is a common chronic relapsing inflammatory skin disease, of which the pathogenesis is a complex interplay between genetics and environment. Although the exact mechanisms of the disease pathogenesis remain unclear, the immune dysregulation primarily involving the Th2 inflammatory pathway and accompanied with an imbalance of multiple immune cells is considered as one of the critical etiologies of AD. Tryptophan metabolism has long been firmly established as a key regulator of immune cells and then affect the occurrence and development of many immune and inflammatory diseases. But the relationship between tryptophan metabolism and the pathogenesis of AD has not been profoundly discussed throughout the literatures. Therefore, this review is conducted to discuss the relationship between tryptophan metabolism and the complex network of skin inflammatory response in AD, which is important to elucidate its complex pathophysiological mechanisms, and then lead to the development of new therapeutic strategies and drugs for the treatment of this frequently relapsing disease.

Integrative analysis of the metabolome and transcriptome reveals the influence of Lactobacillus plantarum CCFM8610 on germ-free mice

This study describes the influence of Lactobacillus plantarum CCFM8610 on the host by employing transcriptome and untargeted metabolomics. According to the enrichment analysis, three pathways, including the complement and coagulation cascade pathway, antigen processing and presentation pathways, and protein processing in the endoplasmic reticulum pathway, were affected by L. plantarum CCFM8610 colonization. According to partial least squares-discriminant analysis, five metabolites, L-methionine, D-tryptophan, indoleacrylic acid, DL-acetylcarnitine, and L-norleucine, were identified as key metabolites in the serum. Furthermore, integrative analysis of the metabolome and transcriptome revealed connections between enriched pathways and differential metabolites, and the regulation strategy of choline by affecting gene expression was proposed. Overall, the effects of L. plantarum CCFM8610 on host health were investigated after excluding the influence of gut microbes, which provides a valuable reference for studying the potential mechanisms of the effect of probiotics on host health.

Lactobacillus salivarius Promotion of Intestinal Stem Cell Activity in Hens Is Associated with Succinate-Induced Mitochondrial Energy Metabolism

Currently, the regulation of Lactobacillus on intestinal stem cells (ISCs) attracts broad attention, but their active ingredients and the underlying mechanism are worthy of further study. Previously, host intestinal commensal bacteria were verified to drive the differentiation of ISCs. In this study, the strong bacteriostatic activity of Lactobacillus salivarius and Lactobacillus agilis were illustrated, and the components (supernatant, precipitation) of L. salivarius or L. agilis were further demonstrated to decrease the differentiation of ISCs in vivo. Interestingly, antibiotics feeding decreased ISCs differentiation in vivo as well. However, the administration of L. salivarius supernatant following antibiotics feeding was shown to promote ISCs differentiation dramatically when compared with the antibiotics feeding group, indicating that some active ingredients existed in its supernatant to promote ISCs activity. Strikingly, in vitro, the treatment of L. salivarius supernatant was further confirmed to promote the intestinal organoids' size, budding, and LGR5 expression. Next, the metabolomics analysis of Lactobacilli' supernatants suggested that succinate might be a crucial metabolite to promote ISCs activity. Further, the succinate treatment in vitro (1000 μM) and in vivo (50 mM) was confirmed to enhance the expression of LGR5 and PCNA. SLC13A3 (a sodium/dicarboxylate cotransporter) was detected in the intestinal organoids and demonstrated to transport succinate into ISCs, as confirmed by the contact of FITC-succinate with ISCs nucleus. Subsequently, high mitochondrial membrane potential and reactive oxygen species levels appeared in the intestinal organoids upon succinate treatment. Collectively, the promotion of L. salivarius on ISCs activity is associated with succinate-induced mitochondrial energy metabolism. IMPORTANCE In our previous study, Lactobacillus salivarius and Lactobacillus agilis were demonstrated to regulate intestinal stem cell activity in hens, but their active ingredients and the underlying mechanism remain unclear. In this study, L. salivarius supernatant was shown to directly promote intestinal stem cell activity. Furthermore, the succinate (a critical metabolite of L. salivarius) was screened out to promote intestinal stem cell activity. Moreover, the succinate was confirmed to enter intestinal stem cells and induce high mitochondrial energy metabolism, finally promoting intestinal stem cell activity. These findings will advance uncovering the mechanism by which Lactobacillus regulate intestinal stem cell activity in chickens.

Lactobacillus salivarius Promotion of Intestinal Stem Cell Activity in Hens Is Associated with Succinate-Induced Mitochondrial Energy Metabolism

Currently, the regulation of Lactobacillus on intestinal stem cells (ISCs) attracts broad attention, but their active ingredients and the underlying mechanism are worthy of further study. Previously, host intestinal commensal bacteria were verified to drive the differentiation of ISCs. In this study, the strong bacteriostatic activity of Lactobacillus salivarius and Lactobacillus agilis were illustrated, and the components (supernatant, precipitation) of L. salivarius or L. agilis were further demonstrated to decrease the differentiation of ISCs in vivo. Interestingly, antibiotics feeding decreased ISCs differentiation in vivo as well. However, the administration of L. salivarius supernatant following antibiotics feeding was shown to promote ISCs differentiation dramatically when compared with the antibiotics feeding group, indicating that some active ingredients existed in its supernatant to promote ISCs activity. Strikingly, in vitro, the treatment of L. salivarius supernatant was further confirmed to promote the intestinal organoids' size, budding, and LGR5 expression. Next, the metabolomics analysis of Lactobacilli' supernatants suggested that succinate might be a crucial metabolite to promote ISCs activity. Further, the succinate treatment in vitro (1000 μM) and in vivo (50 mM) was confirmed to enhance the expression of LGR5 and PCNA. SLC13A3 (a sodium/dicarboxylate cotransporter) was detected in the intestinal organoids and demonstrated to transport succinate into ISCs, as confirmed by the contact of FITC-succinate with ISCs nucleus. Subsequently, high mitochondrial membrane potential and reactive oxygen species levels appeared in the intestinal organoids upon succinate treatment. Collectively, the promotion of L. salivarius on ISCs activity is associated with succinate-induced mitochondrial energy metabolism. IMPORTANCE In our previous study, Lactobacillus salivarius and Lactobacillus agilis were demonstrated to regulate intestinal stem cell activity in hens, but their active ingredients and the underlying mechanism remain unclear. In this study, L. salivarius supernatant was shown to directly promote intestinal stem cell activity. Furthermore, the succinate (a critical metabolite of L. salivarius) was screened out to promote intestinal stem cell activity. Moreover, the succinate was confirmed to enter intestinal stem cells and induce high mitochondrial energy metabolism, finally promoting intestinal stem cell activity. These findings will advance uncovering the mechanism by which Lactobacillus regulate intestinal stem cell activity in chickens.

Effects of Dietary Pectin and Lactobacillus salivarius ATCC 11741 on Growth Performance, Immunocompetence, Gut Microbiota, Antioxidant Capacity, and Disease Resistance in Narrow-Clawed Crayfish, Postantacus leptodactylus

The present study was conducted to clarify the effects of Lactobacillus salivarius (LS) ATCC 11741 and pectin (PE) on growth performance, digestive enzymes activity, gut microbiota composition, immune parameters, antioxidant defense as well as disease resistance against Aeromonas hydrophila in narrow-clawed crayfish, Postantacus leptodactylus. During 18 weeks trial feeding, 525 narrow-clawed crayfish juvenile (8.07 ± 0.1 g) fed with seven experimental diets including control (basal diet), LS1 (1 × 10⁷ CFU/g), LS2 (1 × 109 CFU/g), PE1 (5 g/kg), PE2 (10 g/kg), LS1PE1 (1 × 10⁷ CFU/g +5 g/kg), and LS2PE2 (1 × 109 CFU/g +10 g/kg). After 18 weeks, growth parameters (final weight, weight gain, and specific growth rate) and feed conversion rate were significantly improved in all treatments (P < 0.05). Besides, diets incorporated with LS1PE1 and LS2PE2 significantly increased the activity of amylase and protease enzymes compared to LS1, LS2, and control groups (P < 0.05). Microbiological analyses revealed that the total heterotrophic bacteria count (TVC) and lactic acid bacteria (LAB) of narrow-clawed crayfish fed diets containing LS1, LS2, LS1PE1, and LS2PE2 were higher than control group. The highest total haemocyte count (THC), large-granular (LGC) and semigranular cells (SGC) count, and hyaline count (HC) was obtained in LS1PE1 (P < 0.05). Similarly, higher immunity activity (lysozyme (LYZ), phenoloxidase (PO), nitroxidesynthetase (NOs), and alkaline phosphatase (AKP)) observed in the LS1PE1 treatment compared to the control group (P < 0.05). The glutathione peroxidase (GPx) and superoxide dismutase (SOD) activity remarkably enhanced in LS1PE1 and LS2PE2, while malondialdehyde (MDA) content reduced in these two treatments. In addition, specimens belonging to LS1, LS2, PE2, LS1PE1, and LS2PE2 groups presented higher resistance against A. hydrophila compared to the control group. In conclusion, feeding narrow-clawed crayfish with synbiotic had higher efficiency on growth parameters, immunocompetence, and disease resistance compared to single consumption of prebiotics and probiotics.

The Effect of Indole-3-Lactic Acid from Lactiplantibacillus plantarum ZJ316 on Human Intestinal Microbiota In Vitro

Microbiota-derived tryptophan metabolites are essential signals for maintaining gut homeostasis, yet the potential contribution to modulating gut microbiota has been rarely investigated. In this study, Lactiplantibacillus plantarum ZJ316 (CCTCC No. M 208077) with a high production (43.14 μg/mL) of indole-3-lactic acid (ILA) was screened. ILA with 99.00% purity was prepared by macroporous resin, Sephadex G–25 and reversed-phase high-performance liquid chromatography. Purified ILA can effectively inhibit foodborne pathogens such as Salmonella spp., Staphylococcus spp., Escherichia coli and Listeria monocytogenes. In an in vitro model of the human gut microbiota, a medium-dose ILA (172 mg/L) intervention increased the average relative abundance of phyla Firmicutes and Bacteroidota by 9.27% and 15.38%, respectively, while Proteobacteria decreased by 14.36% after 24 h fermentation. At the genus level, the relative abundance of Bifidobacterium and Faecalibacterium significantly increased to 5.36 ± 2.31% and 2.19 ± 0.77% (p < 0.01), respectively. Escherichia and Phascolarctobacterium decreased to 16.41 ± 4.81% (p < 0.05) and 2.84 ± 1.02% (p < 0.05), respectively. Intestinal short-chain fatty acids, especially butyric acid, were significantly increased (2.98 ± 0.72 µmol/mL, p < 0.05) and positively correlated with Oscillospira and Collinsella. Overall, ILA has the potential to regulate the gut microbiota, and an in-depth understanding of the relationship between tryptophan metabolites and gut microbiota is needed in the future.

Potential roles of gut microbial tryptophan metabolites in the complex pathogenesis of acne vulgaris

Acne vulgaris is a chronic inflammatory skin disease in which the influence of gut microbiota has been implicated but without clarification of mechanisms. Gut microbiota may exert such an influence via metabolites, particularly those of tryptophan. End metabolites of tryptophan activate receptors, including aryl hydrocarbon, G protein-coupled, and pregnane X receptors to stabilize the immune microenvironment and intestinal mucosal homeostasis. Any impact on the pathogenesis of acne vulgaris remains unclear. The current review collates recent advances concerning potential roles of tryptophan metabolism in mediating skin inflammation, follicular sebaceous gland function and intestinal permeability, all of which influence the pathogenesis of acne vulgaris. The aim was to improve understanding of the pathogenesis of acne vulgaris and to expose therapeutic opportunities.

Tryptophan regulates bile and nitrogen metabolism in two pig gut lactobacilli species in vitro based on metabolomics study

Research has demonstrated that tryptophan (Trp) regulated the composition and metabolism of the gut microbiota. However, the detailed mode of action of Trp on the metabolism of intestinal commensal lactobacilli has not been well characterized. This study aimed to compare the effects of Trp concentration (0.2, 0.4, 0.6 mmol/L) in the media on the metabolism of Lactobacillus amylovorus and Limosilactobacillus mucosae isolated from the small intestine of piglets in vitro by high-performance liquid chromatography and metabolomics study. Results showed that increased Trp concentration increased (P < 0.05) net utilization of lysine, methionine, tryptophan, asparagine/aspartate, glutamine/glutamate, however, increased net production of glycine and taurine in Lac. amylovorus. In contrast, increased Trp concentration decreased (P < 0.05) net utilization of leucine, phenylalanine, and serine and increased (P < 0.05) net utilization of arginine and net production of ornithine and glycine in Lim. mucosae. Targeted metabolomics analysis showed that increased Trp concentration promoted (P < 0.05) the production of indole-3-lactic acid and 3-indoleacetic acid in the two lactobacilli strains. Increased concentration of Trp increased (P < 0.01) glycochenodeoxycholic acid metabolism in Lim. mucosae and glycocholic acid and taurocholic acid metabolism in Lac. amylovorus. Untargeted metabolomics analysis showed that metabolic pathways related to phenylalanine and tryptophan metabolism, and nicotinate and nicotinamide metabolism were regulated by Trp in Lim. mucosae. These findings will help develop new biomarkers and dietary strategies to maintain the functionality of the gut microbiota aiming at improving the nutrition and health of both humans and animals.

The Probiotic Properties of Lactic Acid Bacteria and Their Applications in Animal Husbandry

The intestinal tract of animals is a complex ecosystem in which nutrients, microbiota and host cells interact extensively. Probiotics can be considered as part of the natural microbiota of the gut and are involved in improving homeostasis. Lactic acid bacteria (LAB) is a general term for a class of non-spore forming, gram-positive bacteria whose main product of fermented sugar is lactic acid. LAB are considered to be a type of probiotic due to their health-promoting effects on the host, and are very effective in the treatment of human and animal diseases. LAB have been widely used as a class of microbial agents in the field of livestock and poultry breeding. They are also considered to be the best substitutes for antibiotics to improve animal health. Here, we review the biological functions, probiotic characteristics and applications of LAB in livestock and poultry breeding. This review is designed to provide a theoretical base for the in-depth exploration and promotion of LAB use in animal diets.

Microbiota-Host-Irinotecan Axis: A New Insight Toward Irinotecan Chemotherapy

Irinotecan (CPT11) and its active metabolite ethyl-10-hydroxy-camptothecin (SN38) are broad-spectrum cytotoxic anticancer agents. Both cause cell death in rapidly dividing cells (e.g., cancer cells, epithelial cells, hematopoietic cells) and commensal bacteria. Therefore, CPT11 can induce a series of toxic side-effects, of which the most conspicuous is gastrointestinal toxicity (nausea, vomiting, diarrhea). Studies have shown that the gut microbiota modulates the host response to chemotherapeutic drugs. Targeting the gut microbiota influences the efficacy and toxicity of CPT11 chemotherapy through three key mechanisms: microbial ecocline, catalysis of microbial enzymes, and immunoregulation. This review summarizes and explores how the gut microbiota participates in CPT11 metabolism and mediates host immune dynamics to affect the toxicity and efficacy of CPT11 chemotherapy, thus introducing a new concept that is called "microbiota-host-irinotecan axis". Also, we emphasize the utilization of bacterial β-glucuronidase-specific inhibitor, dietary interventions, probiotics and strain-engineered interventions as emergent microbiota-targeting strategies for the purpose of improving CPT11 chemotherapy efficiency and alleviating toxicity.

Biomodification of acenocoumarol by bifidobacteria

The increased interest of consumers in probiotic foods requires a deeper knowledge on the possible interactions with drugs, because their pharmacological properties could be modified. In this context, these studies are relevant for drugs such as acenocoumarol, whose dosage must be controlled due to, among other factors, food-drug interactions. Acenocoumarol is an oral anticoagulant with a narrow therapeutic range. The aim of the present research is to evaluate, in vitro, the effect of bifidobacteria on acenocoumarol. The drug was incubated with Bifidobacterium bifidum CIDCA 5310 or Bifidobacterium adolescentis CIDCA 5317 in MRS broth at 37°C for 24 h in anaerobic conditions. The effect of incubation with sterilized spent culture supernatants (SSCS) was also evaluated. Analysis by RP-HPLC showed that both bifidobacterial strains reduced the area of the acenocoumarol peak and two new peaks were evidenced. In addition, a decrease in the intensity of the bands at 1650, 1390 and 1110/cm was observed in the FTIR spectroscopic determinations. Moreover, a new band appeared at 1720/cm. No effect on the drug was observed when incubation was performed with SSCS. The present study showed a significant change in the concentration of the anticoagulant after incubation with bifidobacteria and results are compatible with biomodification of the drug due to enzymatic activity of bifidobacteria.