Design of a novel gut bacterial adhesion model for probiotic applications

In Vitro Human Gastrointestinal Tract Simulation Systems: A Panoramic Review

Simulated human gastrointestinal (GI) tract systems are important for their applications in the fields of probiotics, nutrition and health. To date, various in vitro gut systems have been available to study GI tract dynamics and its association with health. In contrast to in vivo investigations, which are constrained by ethical considerations, in vitro models have several benefits despite the challenges involved in mimicking the GI environment. These in vitro models can be used for a range of research, from simple to dynamic, with one compartment to several compartments. In this review, we present a panoramic development of in vitro GI models for the first time through an evolutionary timeline. We tried to provide insight on designing an in vitro gut model, especially for novices. Latest developments and scope for improvement based on the limitations of the existing models were highlighted. In conclusion, designing an in vitro GI model suitable for a particular application is a multifaceted task. The bio-mimicking of the GI tract specific to geometrical, anatomical and mechanical features remains a challenge for the development of effective in vitro GI models. Advances in computer technology, artificial intelligence and nanotechnology are going to be revolutionary for further development. Besides this, in silico high-throughput technologies and miniaturisation are key players in the success of making in vitro modelling cost-effective and reducing the burden of in vivo studies.

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.

Effects of Quadruple Therapy Combined with Probiotics on Helicobacter Pylori-Related Peptic Ulcer

The present study was designed to observe the effect of quadruple therapy combined with probiotics on Helicobacter pylori-related peptic ulcer. The patients in the control group (n = 90) were given regular quadruple therapy including proton pump inhibitor ilaprazole enteric-coated tablet + two antibiotics amoxicillin dispersible tablet and metronidazole tablet + colloidal bismuth pectin capsule for 2 weeks. Patients in the study group (n = 90) were given abovementioned quadruple therapy combined with probiotics live combined Bifidobacterium, Lactobacillus, and Enterococcus Capsules, oral for 2 weeks. Then Hp clearance rate, recurrence rate, levels of gastrointestinal hormone makers, and advance reactions between two groups were compared. At the 2nd week after the treatment, the Helicobacter pylori clearance rate in the study group (87.79%) was significantly higher than the control group (78.89%), and the total recurrence rate in the study group (6.67%) was significantly lower than the control group (13.33%) (P < 0.05). Serum gastrin and motilin expression were lower, and somatostatin expressions was significantly higher than those in the control group (P < 0.05). There was no significant difference in the total incidence of adverse reactions between the two groups (P > 0.05). In summary, quadruple therapy combined with probiotics in the treatment of Helicobacter pylori-related peptic ulcer can improve the Helicobacter pylori clearance rate, reduce the Helicobacter pylori recurrence rate, and is beneficial to improving the level of gastrointestinal hormones, with certain safety.

A simple, quantitative assay for the detection of viable but non-culturable (VBNC) bacteria

This protocol determines the fraction of a bacterial population that is viable and culturable, viable and non-culturable, or non-viable (dead). Each population is detected by isolating colonies on agar plates, performing direct counts, and staining for live or dead cells. Its application is limited to bacteria that are stainable and when permissible growth conditions are known. The quantitative data extracted allow for the detection of a viable but non-culturable (alive and non-dividing) population from a liquid culture.

For complete details on the use and execution of this protocol, please refer to Stott et al. (2015).

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Liquid cultures are spread onto agar plates to quantify CFU/mL

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Direct counting is performed to determine the total number of bacteria per mL

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Fluorescence microscopy is used to distinguish between live and dead bacteria

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In sum, the protocol can reveal VBNC populations in a culture

Helicobacter pylori treatment: antibiotics or probiotics

Treatment of Helicobacter pylori infection is important for the management of gastrointestinal disorders such as peptic ulcer and gastric cancer. Due to the increase in the prevalence of H. pylori resistance to antibiotics, triple therapy with clarithromycin is no longer the best treatment for H. pylori, especially in some areas where the local resistance to this antibiotic is higher than 20%. Alternative treatments have been proposed for the eradication of H. pylori. Some of them including novel antibiotics or classical ones in different combinations; these treatments are being used in the regular clinical practice as novel and more effective treatments. Others therapies are using probiotics associated to antibiotics to treat this infection.The present article is a revision of H. pylori eradication treatment, focusing on emerging approaches to avoid the treatment failure, using new therapies with antimicrobials or with probiotics.

Investigating cholesterol metabolism and ageing using a systems biology approach

CVD accounted for 27 % of all deaths in the UK in 2014, and was responsible for 1·7 million hospital admissions in 2013/2014. This condition becomes increasingly prevalent with age, affecting 34·1 and 29·8 % of males and females over 75 years of age respectively in 2011. The dysregulation of cholesterol metabolism with age, often observed as a rise in LDL-cholesterol, has been associated with the pathogenesis of CVD. To compound this problem, it is estimated by 2050, 22 % of the world's population will be over 60 years of age, in culmination with a growing resistance and intolerance to pre-existing cholesterol regulating drugs such as statins. Therefore, it is apparent research into additional therapies for hypercholesterolaemia and CVD prevention is a growing necessity. However, it is also imperative to recognise this complex biological system cannot be studied using a reductionist approach; rather its biological uniqueness necessitates a more integrated methodology, such as that offered by systems biology. In this review, we firstly discuss cholesterol metabolism and how it is affected by diet and the ageing process. Next, we describe therapeutic strategies for hypercholesterolaemia, and finally how the systems biology paradigm can be utilised to investigate how ageing interacts with complex systems such as cholesterol metabolism. We conclude by emphasising the need for nutritionists to work in parallel with the systems biology community, to develop novel approaches to studying cholesterol metabolism and its interaction with ageing.

Transcriptomic Profile of Whole Blood Cells from Elderly Subjects Fed Probiotic Bacteria Lactobacillus rhamnosus GG ATCC 53103 (LGG) in a Phase I Open Label Study

We examined gene expression of whole blood cells (WBC) from 11 healthy elderly volunteers participating on a Phase I open label study before and after oral treatment with Lactobacillus rhamnosus GG-ATCC 53103 (LGG)) using RNA-sequencing (RNA-Seq). Elderly patients (65–80 yrs) completed a clinical assessment for health status and had blood drawn for cellular RNA extraction at study admission (Baseline), after 28 days of daily LGG treatment (Day 28) and at the end of the study (Day 56) after LGG treatment had been suspended for 28 days. Treatment compliance was verified by measuring LGG-DNA copy levels detected in host fecal samples. Normalized gene expression levels in WBC RNA were analyzed using a paired design built within three analysis platforms (edgeR, DESeq2 and TSPM) commonly used for gene count data analysis. From the 25,990 transcripts detected, 95 differentially expressed genes (DEGs) were detected in common by all analysis platforms with a nominal significant difference in gene expression at Day 28 following LGG treatment (FDR<0.1; 77 decreased and 18 increased). With a more stringent significance threshold (FDR<0.05), only two genes (FCER2 and LY86), were down-regulated more than 1.5 fold and met the criteria for differential expression across two analysis platforms. The remaining 93 genes were only detected at this threshold level with DESeq2 platform. Data analysis for biological interpretation of DEGs with an absolute fold change of 1.5 revealed down-regulation of overlapping genes involved with Cellular movement, Cell to cell signaling interactions, Immune cell trafficking and Inflammatory response. These data provide evidence for LGG-induced transcriptional modulation in healthy elderly volunteers because pre-treatment transcription levels were restored at 28 days after LGG treatment was stopped. To gain insight into the signaling pathways affected in response to LGG treatment, DEG were mapped using biological pathways and genomic data mining packages to indicate significant biological relevance.

Trial Registration: ClinicalTrials.gov NCT01274598

Role of NLRP3 inflammasome in Bifidobacterium longum-regulated visceral hypersensitivity of postinfectious irritable bowel syndrome

We aimed to explore the role of NLRP3 inflammasome in Bifidobacterium longum-regulated visceral hypersensitivity of postinfectious irritable bowel syndrome (PI-IBS). Fifty NIH mice were divided into five groups (n = 10). The visceral sensitivities of PI-2W and PI-8W groups significantly exceeded than those of normal control groups (P < 0.05), which was significantly decreased in PI-B group (P < 0.05). Significantly more IL-18 and IL-1β were expressed in PI-2W and PI-8W groups than those in normal control groups (P < 0.05), which was significantly decreased in PI-B group (P < 0.05). Bifidobacterium longum may down-regulate IL-18 and IL-1β expressions by inhibiting NLRP3 inflammasome and thus reduce the visceral hypersensitivity of PI-IBS.