Clinical research on probiotics: the interface between science and regulation

Probiotics, Their Extracellular Vesicles and Infectious Diseases

Probiotics have been shown to be effective against infectious diseases in clinical trials, with either intestinal or extraintestinal health benefits. Even though probiotic effects are strain-specific, some "widespread effects" include: pathogen inhibition, enhancement of barrier integrity and regulation of immune responses. The mechanisms involved in the health benefits of probiotics are not completely understood, but these effects can be mediated, at least in part, by probiotic-derived extracellular vesicles (EVs). However, to date, there are no clinical trials examining probiotic-derived EVs health benefits against infectious diseases. There is still a long way to go to bridge the gap between basic research and clinical practice. This review attempts to summarize the current knowledge about EVs released by probiotic bacteria to understand their possible role in the prevention and/or treatment of infectious diseases. A better understanding of the mechanisms whereby EVs package their cargo and the process involved in communication with host cells (inter-kingdom communication), would allow further advances in this field. In addition, we comment on the potential use and missing knowledge of EVs as therapeutic agents (postbiotics) against infectious diseases. Future research on probiotic-derived EVs is needed to open new avenues for the encapsulation of bioactives inside EVs from GRAS (Generally Regarded as Safe) bacteria. This could be a scientific novelty with applications in functional foods and pharmaceutical industries.

How to select a probiotic? A review and update of methods and criteria

International competition within the dairy market and increasing public awareness about the importance of functional food consumption are providing new challenges for innovation in the probiotic sector. In this context, countless references are currently dedicated to the selection and characterization of new species and more specific strains of probiotic bacteria. In general, these studies adopt basic selection criteria established by the World Health Organization (WHO), including host-associated stress resistance, epithelium adhesion ability, and antimicrobial activity. These aspects are applied to ensure that the candidate probiotic could withstand the stressful conditions of the human digestive system and exert functional proprieties. However, it cannot be assumed that these novel microbial strains are capable of offering several biological benefits attributed to probiotics. Additionally, safety-associated selection criteria, such as plasmid-associated antibiotic resistance spreading and enterotoxin production, are often neglected. This article reviews the recent developments in the processes, strategies, and methods, such as anticarcinogenic, antidepression, antianxiety, antiobesity, antidiabetic, immunostimulatory, and cholesterol-lowering assessments, to select probiotic strains with the ultimate objective of assisting future probiotic microbe evaluation studies.

Probiotics in the treatment of periodontal disease: A systematic review

Over the years, probiotics have been used in the treatment of a variety of diseases. The use of probiotics in the treatment of periodontal disease has caught on over the last decade or so. This review was performed to determine whether administration of probiotics produced a lasting clinical benefit in the treatment of periodontal disease. A MEDLINE, Cochrane database and a hand search was performed on human randomized placebo controlled trials using probiotics in the treatment of periodontal disease. A total of thirteen papers which addressed the question of the use of probiotics in the treatment of periodontal disease were retrieved. Most of the studies reviewed showed only a short term benefit with regards to reduction in gingival inflammation and probing depth reduction. Lasting clinical benefits were not seen in any of the studies. At least four different combinations and strains of probiotics have been used in the studies. There also existed significant heterogeneity in the methodology of the studies reviewed. It was concluded that current regimens of probiotics in the treatment of periodontal disease produce only short-term clinical and microbiologic benefits.

Gut Health in the era of the human gut microbiota: from metaphor to biovalue

The human intestinal ecosystem, previously called the gut microflora is now known as the Human Gut Microbiota (HGM). Microbiome research has emphasized the potential role of this ecosystem in human homeostasis, offering unexpected opportunities in therapeutics, far beyond digestive diseases. It has also highlighted ethical, social and commercial concerns related to the gut microbiota. As diet factors are accepted to be the major regulator of the gut microbiota, the modulation of its composition, either by antibiotics or by food intake, should be regarded as a fascinating tool for improving the human health. Scientists, the food industry, consumers and policymakers alike are involved in this new field of nutrition. Defining how knowledge about the HGM is being translated into public perception has never been addressed before. This raises the question of metaphors associated with the HGM, and how they could be used to improve public understanding, and to influence individual decision-making on healthcare policy. This article suggests that a meeting of stakeholders from the social sciences, basic research and the food industry, taking an epistemological approach to the HGM, is needed to foster close, innovative partnerships that will help shape public perception and enable novel behavioural interventions that would benefit public health.

Evidence-based guidelines for use of probiotics in preterm neonates

BACKGROUND

Current evidence indicates that probiotic supplementation significantly reduces all-cause mortality and definite necrotising enterocolitis without significant adverse effects in preterm neonates. As the debate about the pros and cons of routine probiotic supplementation continues, many institutions are satisfied with the current evidence and wish to use probiotics routinely. Because of the lack of detail on many practical aspects of probiotic supplementation, clinician-friendly guidelines are urgently needed to optimise use of probiotics in preterm neonates.

AIM

To develop evidence-based guidelines for probiotic supplementation in preterm neonates.

METHODS

To develop core guidelines on use of probiotics, including strain selection, dose and duration of supplementation, we primarily used the data from our recent updated systematic review of randomised controlled trials. For equally important issues including strain identification, monitoring for adverse effects, product format, storage and transport, and regulatory hurdles, a comprehensive literature search, covering the period 1966-2010 without restriction on the study design, was conducted, using the databases PubMed and EMBASE, and the proceedings of scientific conferences; these data were used in our updated systematic review.

RESULTS

In this review, we present guidelines, including level of evidence, for the practical aspects (for example, strain selection, dose, duration, clinical and laboratory surveillance) of probiotic supplementation, and for dealing with non-clinical but important issues (for example, regulatory requirements, product format). Evidence was inadequate in some areas, and these should be a target for further research.

CONCLUSION

We hope that these evidence-based guidelines will help to optimise the use of probiotics in preterm neonates. Continued research is essential to provide answers to the current gaps in knowledge about probiotics.

The prophylactic use of probiotics in the prevention of radiation therapy-induced diarrhea

Cancer treatment regimens that include radiation therapy (RT) to the abdominal region for cervical, ovarian, prostate, sigmoid, or colorectal cancer potentially disturb the colonization resistance of the indigenous gut flora, causing RT-induced diarrhea, enteritis, and colitis in more than 80% of patients with cancer. One approach for the prevention of RT-induced diarrhea is the use of probiotics. Randomized clinical trials have demonstrated efficacy of probiotic preparations VSL #3 and Lactobacillus casei DN-114 001 in decreasing the incidence and grade of RT-induced diarrhea. Oncology nurses and advanced practice clinicians are in a position to interpret research findings related to RT-induced diarrhea, enteritis, and colitis and to apply evidence-based practice principles in patients with cancer receiving RT to promote positive outcomes.