Improvement of gastrointestinal health status in subjects consumingLactobacillus reuteriNCIMB 30242 capsules: apost-hocanalysis of a randomized controlled trial

Emerging Insights into the Endocrine Regulation of Bone Homeostasis by Gut Microbiome

Gut microbiota plays an important role in the regulation of bone homeostasis and bone health. Recent studies showed that these effects could be mediated through microbial metabolites released by the microbiota like short-chain fatty acids, metabolism of endogenous molecules such as bile acids, or a complex interplay between microbiota, the endocrine system, and the immune system. Importantly, some studies showed a reciprocal relationship between the endocrine system and gut microbiota. For instance, postmenopausal estrogen deficiency could lead to dysbiosis of the gut microbiota, which could in turn affect various immune response and bone remodeling. In addition, evidence showed that shift in the indigenous gut microbiota caused by antibiotics treatment may also impact normal skeletal growth and maturation. In this mini-review, we describe recent findings on the role of microbiome in bone homeostasis, with a particular focus on molecular mechanisms and their interactions with the endocrine and immune system. We will also discuss the recent findings on estrogen deficiency and microbiota dysbiosis, and the clinical implications for the development of new therapeutic strategies for osteoporosis and other bone disorders.

Lactobacillus reuteri in digestive system diseases: focus on clinical trials and mechanisms

Objectives

Digestive system diseases have evolved into a growing global burden without sufficient therapeutic measures. Lactobacillus reuteri (L. reuteri) is considered as a new potential economical therapy for its probiotic effects in the gastrointestinal system. We have provided an overview of the researches supporting various L. reuteri strains' application in treating common digestive system diseases, including infantile colic, diarrhea, constipation, functional abdominal pain, Helicobacter pylori infection, inflammatory bowel disease, diverticulitis, colorectal cancer and liver diseases.

Methods

The summarized literature in this review was derived from databases including PubMed, Web of Science, and Google Scholar.

Results

The therapeutic effects of L. reuteri in digestive system diseases may depend on various direct and indirect mechanisms, including metabolite production as well as modulation of the intestinal microbiome, preservation of the gut barrier function, and regulation of the host immune system. These actions are largely strain-specific and depend on the activation or inhibition of various certain signal pathways. It is well evidenced that L. reuteri can be effective both as a prophylactic measure and as a preferred therapy for infantile colic, and it can also be recommended as an adjuvant strategy to diarrhea, constipation, Helicobacter pylori infection in therapeutic settings. While preclinical studies have shown the probiotic potential of L. reuteri in the management of functional abdominal pain, inflammatory bowel disease, diverticulitis, colorectal cancer and liver diseases, its application in these disease settings still needs further study.

Conclusion

This review focuses on the probiotic effects of L. reuteri on gut homeostasis via certain signaling pathways, and emphasizes the importance of these probiotics as a prospective treatment against several digestive system diseases.

Real-Time PCR Assays for the Specific Identification of Probiotic Strains Lactobacillus gasseri BNR17 and Lactobacillus reuteri LRC (NCIMB 30242)

The broad spectrum of health benefits attributed to probiotics has contributed to a rapid increase in the value of the probiotic market. Probiotic health benefits can be strain specific. Thus, strain-level identification of probiotic strains is of paramount importance to ensure probiotic efficacy. Both Lactobacillus gasseri BNR17 and Lactobacillus reuteri LRC (NCIMB 30242) strains have clinically proven health benefits; however, no assays were developed to enable strain-level identification of either of these strains. The objective of this study is to develop strain-specific PCR-based methods for Lactobacillus gasseri BNR17 and Lactobacillus reuteri LRC strains, and to validate these assays according to the guidelines for validating qualitative real-time PCR assays. Using RAST (Rapid Annotation using Subsystem Technology), unique sequence regions were identified in the genome sequences of both strains. Probe-based assays were designed and validated for specificity, sensitivity, efficiency, repeatability, and reproducibility. Both assays were specific to target strain with 100% true positive and 0% false positive rates. Reaction efficiency for both assays was in the range of 90 to 108% with R square values > 0.99. Repeatability and reproducibility were evaluated using five samples at three DNA concentrations each and relative standard deviation was < 4% for repeatability and < 8% for reproducibility. Both of the assays developed and validated in this study for the specific identification of Lactobacillus gasseri BNR17 and Lactobacillus reuteri LRC strains are specific, sensitive, and precise. These assays can be applied to evaluate and ensure compliance in probiotic products.

Bio-functional properties of probiotic Lactobacillus: current applications and research perspectives

Lactic acid bacteria as a starter culture are very important component in the fermentation process of dairy and food industry. Application of lactic acid bacteria as probiotic bacteria adds more functionality to the developed product. Gut colonizing bacteria have attractive benefits related to human health. Bio-functional properties such as antimicrobial activity, anti-inflammatory, ACE-inhibitory, antioxidant, antidiarrheal, antiviral, immunomodulatory, hypocholesterolemic, anti-diabetic and anti-cancer activities are the most applicable research areas of lactic acid bacteria. Different strains of Lactobacillus are generally consumed as probiotics and colonize the gastrointestinal tract. Sometimes these bacteria may possess antimicrobial activity and may positively influence the effect of antibiotics. Use of Lactobacillus spp. for the development of functional foods is one of the promising areas of current research and applications. Individual bacterial species have unique biological activity, which may vary from strains to strains and identification of this uniqueness could be helpful in the development of functional and therapeutic food products.

The Role of the Gut Microbiome in Nonalcoholic Fatty Liver Disease

Nonalcoholic fatty liver disease (NAFLD) is the leading cause of chronic liver disease, with prevalence increasing in parallel with the rising incidence in obesity. Believed to be a "multiple-hit" disease, several factors contribute to NAFLD initiation and progression. Of these, the gut microbiome is gaining interest as a significant factor in NAFLD prevalence. In this paper, we provide an in-depth review of the progression of NAFLD, discussing the mechanistic modes of hepatocyte injury and the potential role for manipulation of the gut microbiome as a therapeutic strategy in the prevention and treatment of NAFLD.

Safety of transtympanic application of probiotics in a chinchilla animal model

Background

Chronic suppurative otitis media can be recalcitrant and difficult to treat, particularly with the increasing occurrence of antibiotic resistance. Lactobacillus plantarum is a probiotic that has been shown to decrease S. aureus and P. aeruginosa growth in wounds, making it a good candidate for the treatment of chronic suppurative otitis media. However, before it can be applied in the ear, its ototoxicity potential must be evaluated.

Methods

A prospective controlled trial was conducted in a chinchilla animal model at the Animal care research facilities of the Montreal Children’s Hospital Research Institute to determine whether Lactobacillus plantarum is ototoxic when applied transtympanically. Ten chinchillas each had one ear randomly assigned to receive 10⁹ CFU/mL of Lactobacillus plantarum solution, while the contralateral ear received saline. Auditory brainstem responses were measured bilaterally at 8, 20, 25 kHz before, at 7–10 days after application, and at 28 days after application of probiotic or saline. Facial nerve and vestibular function were assessed clinically.

Results

There were no statistically significant differences in hearing thresholds between control and experimental ears at 28 days after application. A difference of 11 dB was noted in the 25 kHz range at day 7–10, but resolved by day 28. No animals receiving probiotics developed vestibular nerve dysfunction. There was no histologic evidence of auditory hair cell damaged evidenced by scanning electron microscopy.

Conclusion

Our study suggests that a single application of Lactobacillus plantarum at 10⁹ CFU/mL does not cause ototoxicity in a chinchilla animal model. These preliminary safety evaluations and the pathogen inhibitory effects of L. plantarum demonstrated by previous studies present this probiotic as a candidate of interest for further investigation.

Electronic supplementary material

The online version of this article (10.1186/s40463-017-0242-y) contains supplementary material, which is available to authorized users.

Study and use of the probiotic Lactobacillus reuteri in pigs: a review

Probiotics are living microorganisms that provide a wide variety of health benefits to the host when ingested in adequate amounts. The bacterial strains most frequently used as probiotic agents are lactic acid bacteria, such as Lactobacillus reuteri, which is one of the few endogenous Lactobacillus species found in the gastrointestinal tract of vertebrates, including humans, rats, pigs and chickens. L. reuteri is one of the most well documented probiotic species and has been widely utilized as a probiotic in humans and animals for many years. Initially, L. reuteri was used in humans to reduce the incidence and the severity of diarrhea, prevent colic and necrotic enterocolitis, and maintain a functional mucosal barrier. As interest in alternatives to in-feed antibiotics has grown in recent years, some evidence has emerged that probiotics may promote growth, improve the efficiency of feed utilization, prevent diarrhea, and regulate the immune system in pigs. In this review, the characteristics of L. reuteri are described, in order to update the evidence on the efficacy of using L. reuteri in pigs.

Emerging science of the human microbiome

The human gastrointestinal tract hosts a large number of microbial cells which exceed their mammalian counterparts by approximately 3-fold. The genes expressed by these microorganisms constitute the gut microbiome and may participate in diverse functions that are essential to the host, including digestion, regulation of energy metabolism, and modulation of inflammation and immunity. The gut microbiome can be modulated by dietary changes, antibiotic use, or disease. Different ailments have distinct associated microbiomes in which certain species or genes are present in different relative quantities. Thus, identifying specific disease-associated signatures in the microbiome as well as the factors that alter microbial populations and gene expression will lead to the development of new products such as prebiotics, probiotics, antimicrobials, live biotherapeutic products, or more traditional drugs to treat these disorders. Gained knowledge on the microbiome may result in molecular lab tests that may serve as personalized tools to guide the use of the aforementioned products and monitor interventional progress.

The human microbiome and bile acid metabolism: dysbiosis, dysmetabolism, disease and intervention

INTRODUCTION

Recent evidence indicates that the human gut microbiome plays a significant role in health and disease. Dysbiosis, defined as a pathological imbalance in a microbial community, is becoming increasingly appreciated as a 'central environmental factor' that is both associated with complex phenotypes and affected by host genetics, diet and antibiotic use. More recently, a link has been established between the dysmetabolism of bile acids (BAs) in the gut to dysbiosis.

AREAS COVERED

BAs, which are transformed by the gut microbiota, have been shown to regulate intestinal homeostasis and are recognized as signaling molecules in a wide range of metabolic processes. This review will examine the connection between BA metabolism as it relates to the gut microbiome and its implication in health and disease.

EXPERT OPINION

A disrupted gut microbiome, including a reduction of bile salt hydrolase (BSH)-active bacteria, can significantly impair the metabolism of BAs and may result in an inability to maintain glucose homeostasis as well as normal cholesterol breakdown and excretion. To better understand the link between dysbiosis, BA dysmetabolism and chronic degenerative disease, large-scale metagenomic sequencing studies, metatranscriptomics, metaproteomics and metabolomics should continue to catalog functional diversity in the gastrointestinal tract of both healthy and diseased populations. Further, BSH-active probiotics should continue to be explored as treatment options to help restore metabolic levels.