Lacticaseibacillus rhamnosus Strain GG (LGG) Regulate Gut Microbial Metabolites, an In Vitro Study Using Three Mature Human Gut Microbial Cultures in a Simulator of Human Intestinal Microbial Ecosystem (SHIME)

Functional foods acting on gut microbiota-related wellness: The multi-unit in vitro colon model to assess gut ecological and functional modulation

The aim of this study was to investigate the effect of a functional probiotic cheese (FPC) on gut microbiota (GM), after simulated digestion performed by a multi-unit in vitro colon model (MICODE). Squacquerone-like cheese was produced using the starter Streptococcus thermophilus (control, CTRL), and supplemented with the probiotic Lacticaseibacillus rhamnosus, which was either subjected to high pressure homogenization (LrH) or not (Lr). Samples were stratified by cheese type, storage time, and colonic fermentation phase. Samples were then digested with MICODE and digests were characterized for ecological and functional profiles. The lactobacilli detected in Lr and LrH cheeses (9.0 log CFU/g) were represented by the probiotic strain L. rhamnosus and remained unchanged after storage at 4 °C. Lactobacilli levels in CTRLs increased from 1.5 log CFU/g to 2.0 log CFU/g after six days at 4 °C, while total coliforms remained below 1.5 log CFU/g in all samples. Real-time qPCR indicated a positive GM response after FPC simulated digestion, highlighting an abundance of bifidobacteria, lactobacilli and Clostridium group IV in LrH samples. Metataxonomy revealed higher levels of Firmicutes and Proteobacteria (p ≤ 0.05) after simulated digestion, as well as Megasphaera, Escherichia, Prevotella and Dorea. Moreover, an increase of short and medium chain fatty acids were detected by metabolomics. Overexpression of inferred KEGG metabolic pathways showed mainly fatty acids, novobiocin and amino acid metabolism. Understanding how functional foods can modify the GM may lead to the development of targeted microbiome-based therapies and the exploitation of these foods for the benefit of human health.

Establishment of a Low-Cost and Efficient In Vitro Model for Cultivating Intestinal Microbiota

The Simulator of Human Intestinal Microbial Ecosystem (SHIME) has hindered widespread adoption due to its high cost. This study founded biomimetic multilink fermentation equipment (BMLFE), priced at half or even lower than SHIME. It was improved based on multilink fermentation equipment (MLFE) by modifying materials, peristaltic pumps, fermentation time, and dietary habits while calculating transfer time and volumes and conducted anaerobic fermentation for 15 days followed by monitoring changes in intestinal microbial composition and short-chain fatty acids (SCFAs). We observed that the intestinal microbiota achieved a stable state after the ninth day and retained the predominant bacterial species in the fecal inoculum. The Bacillota/Bacteroidota values of the descending colon (DC) were similar to those in the fecal samples. However, the stability of SCFAs was relatively delayed and reached stability only after the 11th day. Meanwhile, the concentration ratio of acetic acid, propionate, and butyric acid metabolized by transverse colon (TC) and DC on the 11-15th days was close to that in fecal inoculations. Therefore, BMLFE can be used to simulate the human gastrointestinal environment in vitro studies. It is expected to be employed in clinical FMT and may even contribute to establishing stable enterotypes through dietary intervention.

Maternal Supplementation with Lacticaseibacillus rhamnosus GG Improves Glucose Tolerance and Modulates the Intestinal Microbiota of Offspring

INTRODUCTION

Consuming hypercaloric diets during pregnancy induces metabolic, immune, and maternal intestinal dysbiosis disorders. These conditions are transferred to the offspring through the placenta and breastfeeding, increasing susceptibility to metabolic diseases. We investigated the effect of L. rhamnosus GG supplementation on offspring maternally programmed with a hypercaloric diet.

METHODS

Our study involved sixteen female Wistar rats aged ten weeks, which were divided into four groups based on their diets: control (Ctrl), cafeteria (CAF), control + probiotic (PRO), and cafeteria + probiotic (CPRO). The control + probiotic and cafeteria + probiotic groups received a daily oral administration of 250 μL of L. rhamnosus GG cell suspension (equivalent to 109 UFC) for nine weeks. The body weight of the animals was recorded weekly, and their food intake was monitored every 24 h. An oral glucose tolerance test was conducted on the offspring at seven weeks of age. At the ninth week of age, animals were euthanized, and blood, tissues, and organs were collected.

RESULTS

Maternal supplementation with L. rhamnosus GG decreased food intake and the average birth weight, improved glucose sensitivity, and lowered the levels of LDL, cholesterol, triglycerides, and mesenteric adipose tissue in offspring compared with the control and cafeteria groups.

CONCLUSIONS

Our findings indicate that supplementing with LGG during maternal programming could protect offspring from metabolic disruptions caused by a hypercaloric maternal diet.

AhR ligands from LGG metabolites promote piglet intestinal ILC3 activation and IL-22 secretion to inhibit PEDV infection

In maintaining organismal homeostasis, gut immunity plays a crucial role. The coordination between the microbiota and the immune system through bidirectional interactions regulates the impact of microorganisms on the host. Our research focused on understanding the relationships between substantial changes in jejunal intestinal flora and metabolites and intestinal immunity during porcine epidemic diarrhea virus (PEDV) infection in piglets. We discovered that Lactobacillus rhamnosus GG (LGG) could effectively prevent PEDV infection in piglets. Further investigation revealed that LGG metabolites interact with type 3 innate lymphoid cells (ILC3s) in the jejunum of piglets through the aryl hydrocarbon receptor (AhR). This interaction promotes the activation of ILC3s and the production of interleukin-22 (IL-22). Subsequently, IL-22 facilitates the proliferation of IPEC-J2 cells and activates the STAT3 signaling pathway, thereby preventing PEDV infection. Moreover, the AhR receptor influences various cell types within organoids, including intestinal stem cells (ISCs), Paneth cells, and enterocytes, to promote their growth and development, suggesting that AhR has a broad impact on intestinal health. In conclusion, our study demonstrated the ability of LGG to modulate intestinal immunity and effectively prevent PEDV infection in piglets. These findings highlight the potential application of LGG as a preventive measure against viral infections in livestock.IMPORTANCEWe observed high expression of the AhR receptor on pig and human ILC3s, although its expression was negligible in mouse ILC3s. ILC3s are closely related to the gut microbiota, particularly the secretion of IL-22 stimulated by microbial signals, which plays a crucial regulatory role in intestinal immunity. In our study, we found that metabolites produced by beneficial gut bacteria interact with ILC3s through AhR, thereby maintaining intestinal immune homeostasis in pigs. Moreover, LGG feeding can enhance the activation of ILC3s and promote IL-22 secretion in the intestines of piglets, ultimately preventing PEDV infection.

Unraveling the gut-skin axis in atopic dermatitis: exploiting insights for therapeutic strategies

Gut microbiota exert functions of high importance in the intestine. Furthermore, there is increasing evidence for its role in immune regulation and maintenance of homeostasis in many physiological processes taking place in distant tissues. In particular, in this review, we explore the impact of metabolites produced by the gut microbiota on the development of atopic dermatitis (AD). Probiotics and prebiotics balance the microbiota and promote the generation of bacterial metabolites, such as short-chain fatty acids and tryptophan derivates, which promote the regulation of the exacerbated AD immune response through regulatory T cells and IL-10 and TGF-β cytokines. Metabolites also have a direct action on keratinocytes once they reach the bloodstream. Besides, probiotics decrease the levels of metabolites associated with AD onset, such as phenols. Understanding all these crosstalk processes between the gut and the skin reveals a number of possibilities, mainly through the manipulation of the gut microbiome, which may represent therapeutic strategies that can contribute to the standard treatments of AD patients to improve their quality of life.