Immunoprotective effects of oral intake of heat-killed Lactobacillus pentosus strain b240 in elderly adults: a randomised, double-blind, placebo-controlled trial

Long COVID as a disease of accelerated biological aging: An opportunity to translate geroscience interventions

It has been four years since long COVID-the protracted consequences that survivors of COVID-19 face-was first described. Yet, this entity continues to devastate the quality of life of an increasing number of COVID-19 survivors without any approved therapy and a paucity of clinical trials addressing its biological root causes. Notably, many of the symptoms of long COVID are typically seen with advancing age. Leveraging this similarity, we posit that Geroscience-which aims to target the biological drivers of aging to prevent age-associated conditions as a group-could offer promising therapeutic avenues for long COVID. Bearing this in mind, this review presents a translational framework for studying long COVID as a state of effectively accelerated biological aging, identifying research gaps and offering recommendations for future preclinical and clinical studies.

Unlocking the power of postbiotics: A revolutionary approach to nutrition for humans and animals

Postbiotics, which comprise inanimate microorganisms or their constituents, have recently gained significant attention for their potential health benefits. Extensive research on postbiotics has uncovered many beneficial effects on hosts, including antioxidant activity, immunomodulatory effects, gut microbiota modulation, and enhancement of epithelial barrier function. Although these features resemble those of probiotics, the stability and safety of postbiotics make them an appealing alternative. In this review, we provide a comprehensive summary of the latest research on postbiotics, emphasizing their positive impacts on both human and animal health. As our understanding of the influence of postbiotics on living organisms continues to grow, their application in clinical and nutritional settings, as well as animal husbandry, is expected to expand. Moreover, by substituting postbiotics for antibiotics, we can promote health and productivity while minimizing adverse effects. This alternative approach holds immense potential for improving health outcomes and revolutionizing the food and animal products industries.

Effectiveness of probiotic/prebiotic/synbiotic treatments on anxiety: A systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Anxiety can adversely affect human well-being. This meta-analysis aimed to evaluate the effects of interventions that alter the gut microbes (including probiotics, prebiotics, and synbiotics) on anxiety.

METHODS

A systematic meta-analysis of the effects of probiotics, prebiotics, and synbiotics on anxiety was conducted by searching randomized controlled trials (RCTs) in 13 databases. The primary outcomes were the pre- and post-intervention anxiety scores in the intervention and placebo groups. Anxiety scores were extracted as standard mean differences (SMDs) and pooled based on a random effects model. Subgroup analyses of anxiety scales, health status, gastrointestinal symptoms, flora strains, treatment type, probiotic dose, region, and treatment duration were also performed.

RESULTS

29 RCTs (2035 participants) were included, revealing that both probiotics and synbiotics significantly reduced anxiety scores. Additionally, anxiety scores did not significantly reduce when comparing prebiotics and placebos.

LIMITATIONS

Owing to the small combined effect size of probiotic/prebiotic/synbiotic treatments and the relatively few studies on prebiotics and synbiotics included in the analysis, the findings of probiotic/prebiotic/synbiotic treatments are preliminary.

CONCLUSIONS

Our study indicated that probiotics and synbiotics can reduce anxiety scores; however, it might be premature to conclude their clinical efficacy in alleviating anxiety due to the small effect size. There is no consensus regarding the optimal dose, treatment duration, treatment type, or probiotic strain to improve anxiety. Moreover, the mechanisms by which probiotics and synbiotics improve anxiety remain unclear. More RCTs are needed to determine the mechanisms of action and to identify appropriate markers to clarify their effects.

A meta-analysis of the effect of probiotic administration on age-related sarcopenia

Global increase in the prevalence of age-related diseases, such as sarcopenia, highlights the need of recognizing agents that improve muscle health; however, the evidence synthesis on the impact of probiotic administration on sarcopenia is scarce. To summarize and evaluate findings regarding the effect of supplementation with probiotics on sarcopenia, this meta-analysis was conducted. Using databases, including PubMed, SCOPUS, ISI-Web of Science, and Cochrane Library, interventional studies were included if they investigate the effect of probiotic administration on at least one of the components of sarcopenia up to 6 October 2022. Risk of bias evaluation was conducted using the Cochrane quality assessment tool. The random-effects model which takes between-study variations into account was used to obtain the overall effect sizes. The STATA version 14.0 was used for statistical analyses. Overall, 17 studies were included. There was high certainty of evidence that probiotic supplementation has a beneficial effect on muscle mass (kg) (WMD: 0.55, 95% CI: 0.05, 1.05; I 2: 0.0%, p = .995), and muscle function (WMD: 0.13, 95% CI: 0.03, 0.23; I 2: 65.6%, p = .05). Moreover, administration of probiotics for more than 12 weeks significantly increased muscle strength (WMD: 1.16, 95% CI: 0.88, 1.44; I 2: 0.0%, p = .77). However, probiotic supplementation had no effect on anthropometric indices, including body mass index. Probiotic supplementation could improve muscle mass and muscle function in adults more than 55 years old. The beneficial effect of probiotics on muscle strength could appear after 12 weeks of supplementation.

Oral intake of heat-killed Lactiplantibacillus pentosus ONRICb0240 partially protects mice against SARS-CoV-2 infection

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the ongoing coronavirus pandemic. Besides vaccines and antiviral drugs, probiotics have attracted attention for prevention of SARS-CoV-2 infection. Here, we examined the efficacy of heat-killed Lactiplantibacillus pentosus ONRICb0240 (b240) against SARS-CoV-2 infection in mice. We observed that oral intake of heat-killed b240 did not affect virus titers in the respiratory organs of SARS-CoV-2-infected mice, but did provide partial protection against SARS-CoV-2 infection. In addition, heat-killed b240 treatment suppressed the expression of IL-6, a key proinflammatory cytokine, on Day 2 post-infection. Our results highlight the promising protective role of heat-killed b240 and suggest a possible mechanism by which heat-killed b240 partially protects against SARS-CoV-2 infection by modulating host responses.

Postbiotics: The concept and their use in healthy populations

The term postbiotic was recently defined by an panel of scientists convened by the International Scientific Association of Probiotics and Prebiotics as "a preparation of inanimate microorganisms and/or their components that confers a health benefit on the host." This definition focused on the progenitor microbial cell or cell fragments, not just metabolites, proteins or carbohydrates they might produce. Although such microbe-produced constituents may be functional ingredients of the preparation, they are not required to be present in a postbiotic according to this definition. In this context, terms previously used such as paraprobiotics, ghostbiotics, heat-inactivated probiotics, non-viable probiotics, cell fragments or cell lysates, among others, align with the term postbiotics as conceived by this definition. The applications of postbiotics to infant nutrition and pediatric and adult gastroenterology, mainly, are under development. Some applications for skin health are also underway. As postbiotics are composed of inanimate microorganisms, they cannot colonize the host. However, they can in theory modify the composition or functions of the host microbiota, although evidence for this is scarce. Clinical results are promising, but, overall, there is limited evidence for postbiotics in healthy populations. For example, postbiotics have been studied in fermented infant formulas. The regulation of the term postbiotic is still in its infancy, as no government or international agency around the world has yet incorporated this term in their regulation.

Intake of Lactobacillus paragasseri SBT2055 improves subjective symptoms of common cold during winter season in healthy adults: A randomized, double-blind, placebo-controlled parallel-group comparative study

Objective

Lactobacillus paragasseri SBT2055 (LG2055) has been reported to show immunostimulating effects. This study aimed to investigate the effects of LG2055 on the subjective symptoms of the physical condition in healthy adults.

Materials and methods

In this randomized, double-blind, placebo-controlled, parallel-group comparative study, Japanese individuals aged 20-64 years were recruited. A total of 200 participants were randomly divided into two groups by an independent controller (LG2055 and placebo groups; 100 participants per group). Drinkable yogurts containing LG2055 or lacking LG2055 (placebo) were used as test samples. The participants ingested one bottle of the test sample once a day for 12 weeks. A daily physical health questionnaire survey (about common cold symptoms) was performed as the primary outcome, and immunological and oxidative stress markers in saliva and serum were evaluated as secondary outcomes.

Results

In total, 198 participants completed the scheduled intake of the test samples, and five participants were excluded from the final analysis. Consequently, 193 participants (LG2055 group, n = 97; placebo group, n = 96) in the Per-Protocol Set were included in the efficacy analysis. The cumulative days of each symptom were evaluated, and the LG2055 group showed a significantly higher ratio of "without symptom" in runny nose, plugged nose, sneezing, sore throat, hoarseness, cough, headache, feeling tired, and fever than the placebo group, indicating that the incidence rates of common cold symptoms were lower in the LG2055 group. Additionally, changes in the salivary secretory IgA levels were significantly higher, and the serum derivatives of reactive oxygen metabolites levels were significantly lower in the LG2055 group.

Conclusion

Our study revealed that intake of LG2055 decreased common cold symptoms and improved immune parameters in healthy adults. This suggests that LG2055 contributes to the maintenance of physical conditions by improving the host immune system.

Clinical trial registration

[https://www.umin.ac.jp/ctr/index.htm], identifier [UMIN000045901].

The clinical evidence for postbiotics as microbial therapeutics

An optimally operating microbiome supports protective, metabolic, and immune functions, but disruptions produce metabolites and toxins which can be involved in many conditions. Probiotics have the potential to manage these. However, their use in vulnerable people is linked to possible safety concerns and maintaining their viability is difficult. Interest in postbiotics is therefore increasing. Postbiotics contain inactivated microbial cells or cell components, thus are more stable and exert similar health benefits to probiotics. To review the evidence for the clinical benefits of postbiotics in highly prevalent conditions and consider future potential areas of benefit. There is growing evidence revealing the diverse clinical benefits of postbiotics in many prevalent conditions. Postbiotics could offer a novel therapeutic approach and may be a safer alternative to probiotics. Establishing interaction mechanisms between postbiotics and commensal microorganisms will improve the understanding of potential clinical benefits and may lead to targeted postbiotic therapy.

Postbiotics: From emerging concept to application

The microbiome innovation has resulted in an umbrella term, postbiotics, which refers to non-viable microbial cells, metabolic byproducts and their microbial components released after lysis. Postbiotics, modulate immune response, gene expression, inhibit pathogen binding, maintain intestinal barriers, help in controlling carcinogenesis and pathogen infections. Postbiotics have antimicrobial, antioxidant, and immunomodulatory properties with favorable physiological, immunological, neuro-hormonal, regulatory and metabolic reactions. Consumption of postbiotics relieves symptoms of various diseases and viral infections such as SARS-CoV-2. Postbiotics can act as alternatives for pre-probiotic specially in immunosuppressed patients, children and premature neonates. Postbiotics are used to preserve and enhance nutritional properties of food, elimination of biofilms and skin conditioning in cosmetics. Postbiotics have numerous advantages over live bacteria with no risk of bacterial translocation from the gut to blood, acquisition of antibiotic resistance genes. The process of extraction, standardization, transport, and storage of postbiotic is more natural. Bioengineering techniques such as fermentation technology, high pressure etc., may be used for the synthesis of different postbiotics. Safety assessment and quality assurance of postbiotic is important as they may induce stomach discomfort, sepsis and/or toxic shock. Postbiotics are still in their infancy compared to pre- and pro- biotics but future research in this field may contribute to improved physiological functions and host health. The current review comprehensively summarizes new frontiers of research in postbiotics.

The gut microbiome as a modulator of healthy ageing

The gut microbiome is a contributory factor in ageing-related health loss and in several non-communicable diseases in all age groups. Some age-linked and disease-linked compositional and functional changes overlap, while others are distinct. In this Review, we explore targeted studies of the gut microbiome of older individuals and general cohort studies across geographically distinct populations. We also address the promise of the targeted restoration of microorganisms associated with healthier ageing.

Effect of Probiotics on Psychiatric Symptoms and Central Nervous System Functions in Human Health and Disease: A Systematic Review and Meta-Analysis

Background: The gut microbiota impacts on central nervous system (CNS) function via the microbiota–gut–brain axis. Thus, therapeutics targeting the gut microbiota such as probiotics have the potential for improving mental health. This meta-analysis synthesizes the evidence regarding the impacts of probiotics on psychological well-being, psychiatric symptoms and CNS functioning. Methods: The Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines were applied for executing this review using the databases PubMed, Web of Science and Cochrane Library. The data were summarized at qualitative and quantitative level. Results: Fifty-four randomized placebo-controlled studies were included, of which 30 were eligible for meta-analysis. If investigated, the probiotics mostly exerted effects on CNS function. Most probiotics did not affect mood, stress, anxiety, depression and psychiatric distress when compared to placebo at the qualitative level. At quantitative level, depression and psychiatric distress improved slightly in the probiotic condition (depression: mean difference −0.37 (95% CI: −0.55, −0.20); p ≤ 0.0001; psychiatric distress: mean difference −0.33 (95% CI: −0.53, −0.13); p = 0.001). Conclusions: To date it is unclear to which extent and in which specific areas next generation probiotics selected and developed for their ability to improve psychiatric condition and potentially other CNS functions are promising.

Mechanisms of Cognitive Impairment in Depression. May Probiotics Help?

Depression is the major cause of disability globally. Apart from lowered mood and accompanying symptoms, it leads to cognitive impairment that altogether predicts disadvantaged social functioning. Reduced cognitive function in depression appears a bit neglected in the field of clinical and molecular psychiatry, while it is estimated to occur in two-thirds of depressed patients and persist in at least one third of remitted patients. This problem, therefore, requires elucidation at the biomolecular and system levels and calls for improvement in therapeutic approach. In this review study, we address the above-mentioned issues by discussing putative mechanisms of cognitive decline in depression: (1) increased oxidative stress and (2) inflammation, (3) disturbed hypothalamus-pituitary-adrenals axis, and (4) reduced monoamines functionality. Moreover, we acknowledge additional underpinnings of cognitive impairment in depressed elderly: (5) vascular-originated brain ischemia and (6) amyloid-beta plaque accumulation. Additionally, by reviewing molecular, pre-clinical and clinical evidence, we propose gut microbiota-targeted strategies as potential adjuvant therapeutics. The study provides a consolidated source of knowledge regarding mechanisms of cognitive impairment in depression and may path the way toward improved treatment options.

Selection of Probiotics in the Prevention of Respiratory Tract Infections and Their Impact on Occupational Health: Scoping Review

The occupational health impact of respiratory infectious diseases is costly to the economy and the health care system. Probiotics are non-pathogenic live microorganisms that, when ingested in adequate amounts, can colonize the intestinal tract, and enhance the immune system. In recent years, numerous studies have described the possible usefulness of certain probiotic strains in the treatment and prevention of respiratory tract infections, with disparate results. In order to assess the possible efficacy and safety of these microorganisms to prevent or ameliorate respiratory tract infections, we systematically searched the bibliographic databases MEDLINE (via Pubmed), EMBASE, The Cochrane library, Scopus, and Web of science, using the descriptors “Respiratory Tract Infections”, “Probiotics”, “Occupational Health”, “Humans”, and “Clinical Trials”. After applying our inclusion and exclusion criteria, 18 studies were accepted for review and critical analysis. Our analysis suggests that a combination of different probiotics, most of them in the genus Bifidobacterium sp. and Lactobacillus sp., could be a good mix to strengthen the immune system and reduce the symptoms of URTIs in the healthy working population.

The Interaction Between Viruses and Intestinal Microbiota: A Review

As the main pathogen threatening human and animal health, viruses can affect the immunity and metabolism of bodies. There are innate microbial barriers in the digestive tract of the body to preserve the homeostasis of the animal body, which directly or indirectly influences the host defence against viral infection. Understanding the interaction between viruses and intestinal microbiota or probiotics is helpful to study the pathogenesis of diseases. Here, we review recent studies on the interaction mechanism between intestinal microbiota and viruses. The interaction can be divided into two aspects: inhibition of viral infection by microbiota and promotion of viral infection by microbiota. The treatment of viral infection by probiotics is summarized.

The Effect of Probiotics on Health Outcomes in the Elderly: A Systematic Review of Randomized, Placebo-Controlled Studies

Increasing evidence suggests that probiotic supplementation may be efficacious in counteracting age-related shifts in gut microbiota composition and diversity, thereby impacting health outcomes and promoting healthy aging. However, randomized controlled trials (RCTs) with probiotics in healthy older adults have utilized a wide variety of strains and focused on several different outcomes with conflicting results. Therefore, a systematic review was conducted to determine which outcomes have been investigated in randomized controlled trials with probiotic supplementation in healthy older adults and what has been the effect of these interventions. For inclusion, studies reporting on randomized controlled trials with probiotic and synbiotic supplements in healthy older adults (defined as minimum age of 60 years) were considered. Studies reporting clinical trials in specific patient groups or unhealthy participants were excluded. In addition to assessment of eligibility and data extraction, each study was examined for risk of bias and quality assessment was performed by two independent reviewers. Due to the heterogeneity of outcomes, strains, study design, duration, and methodology, we did not perform any meta-analyses and instead provided a narrative overview of the outcomes examined. Of 1997 potentially eligible publications, 17 studies were included in this review. The risk of bias was low, although several studies failed to adequately describe random sequence generation, allocation concealment, and blinding. The overall study quality was high; however, many studies did not include sample calculations, and the majority of studies had a small sample size. The main outcomes examined in the trials included microbiota composition, immune-related measurements, digestive health, general well-being, cognitive function, and lipid and other biomarkers. The most commonly assessed outcome with the most consistent effect was microbiota composition; all but one study with this outcome showed significant effects on gut microbiota composition in healthy older adults. Overall, probiotic supplementation had modest effects on markers of humoral immunity, immune cell population levels and activity, as well as the incidence and duration of the common cold and other infections with some conflicting results. Digestive health, general-well-being, cognitive function, and lipid and other biomarkers were investigated in a very small number of studies; therefore, the impact on these outcomes remains inconclusive. Probiotics appear to be efficacious in modifying gut microbiota composition in healthy older adults and have moderate effects on immune function. However, the effect of probiotic supplementation on other health outcomes remains inconclusive, highlighting the need for more well-designed, sufficiently-powered studies to investigate if and the mechanisms by which probiotics impact healthy aging.

Paraprobiotics: A New Perspective for Functional Foods and Nutraceuticals

Probiotics are live microorganisms that confer health benefits on the host. However, in recent years, several concerns on their use have been raised. In particular, industrial processing and storage of probiotic products are still technological challenges as these could severely impair cell viability. On the other hand, safety of live microorganisms should be taken into account, especially when administered to vulnerable people, such as the elderly and immunodeficient individuals. These drawbacks have enhanced the interest toward new products based on non-viable probiotics such as paraprobiotics and postbiotics. In particular, paraprobiotics, defined as "inactivated microbial cells (non-viable) that confer a health benefit to the consumer," hold the ability to regulate the adaptive and innate immune systems, exhibit anti-inflammatory, antiproliferative and antioxidant properties and exert antagonistic effect against pathogens. Moreover, paraprobiotics can exhibit enhanced safety, assure technological and practical benefits and can also be used in products suitable for people with weak immunity and the elderly. These features offer an important opportunity to prompt the market with novel functional foods or nutraceuticals that are safer and more stable. This review provides an overview of central issues on paraprobiotics and highlights the urgent need for further studies aimed at assessing safety and efficacy of these products and their mechanisms of action in order to support decisions of regulatory authorities. Finally, a definition is proposed that unambiguously distinguishes paraprobiotics from postbiotics.

The effect of probiotics on respiratory tract infection with special emphasis on COVID-19: Systemic review 2010-20

To evaluate the effects of probiotics on respiratory tract infection (RTI) a systematic review of randomized controlled trials (RCTs) from January 2010 to January 2020 was conducted. The PubMed, Google Scholar, Embase, Scopus, Clinicaltrials.gov, and International Clinical Trials Registry Platform databases were systematically searched for the following keywords: respiratory tract infection, probiotics, viral infection, COVID-19, and clinical trial. A total of 27 clinical trials conducted on 9433 patients with RTI plus 10 ongoing clinical studies of probiotics intervention in Coronavirus disease 2019 (COVID-19) were reviewed. The review looked at the potency of probiotics for the hindrance and/or treatment of RTI diseases, this may also apply to COVID-19. The review found that probiotics could significantly increase the plasma levels of cytokines, the effect of influenza vaccine and quality of life, as well as reducing the titer of viruses and the incidence and duration of respiratory infections. These antiviral and immune-modulating activities and their ability to stimulate interferon production recommend the use of probiotics as an adjunctive therapy to prevent COVID-19. Based on this extensive review of RCTs we suggest that probiotics are a rational complementary treatment for RTI diseases and a viable option to support faster recovery.

The Effect of Synbiotic and Probiotic Supplementation on Mental Health Parameters in Patients Undergoing Hemodialysis: A Double-blind, Randomized, Placebo-controlled Trial

Introduction

The purpose of this double-blind clinical trial, was to examine the effect of supplementation with the synbiotic and probiotic on the mental health, quality of life, and anemia in HD patients.

Methods

Seventy-five HD patients were randomly assigned to receive the synbiotic (n = 23) as 15 g of prebiotics, 5 g of probiotic powder containing Lactobacillus acidophilus, Bifidobacterium bifidum, Bifidobacterium lactis, and Bifidobacterium longum (2.7 × 107 CFU/g each); probiotics (n = 23) as 5 g probiotics similar to the synbiotic group with 15 g of maltodextrin as placebo; and placebo (n = 19) as 20 g of maltodextrin. Serum hemoglobin (Hb) and albumin (Alb) were measured. Beck depression and anxiety index (BDI/BAI) was used to assess symptoms of depression and anxiety. The health-related quality of life (HRQoL) was assessed using the questionnaire SF-36.

Results

From baseline to 12 weeks, synbiotic and probiotic supplementation resulted in a significant decrease in BDI and BAI score in comparison to the placebo (P < 0.05). Between and intergroup comparison showed no significant changes between the groups in terms of HRQoL. However, the serum Hb level increased significantly in the synbiotic and probiotic group compared to the placebo group (P < 0.001).

Conclusion

Overall, 12 weeks of synbiotic and probiotic supplementation resulted in an improvement in mental health and anemia compared with the placebo, whereas they failed to enhance the quality of life in HD patients.

Effects of Probiotics and Prebiotics on Frailty and Ageing: A Narrative Review

Globally, the population over the age of 60 is growing fast, but people age in different ways. Frailty, shown by the accumulation of age-related deficits, is a state of increased vulnerability to adverse outcomes among people of the same chronological age. Ageing results in a decline in diversity and homeostasis of microbiomes, and gut flora changes are related to health deficit accumulation and adverse health outcomes. In older people, health deficits including inappropriate intake, sarcopenia, physical inactivity, polypharmacy, and social vulnerability are factors associated with gut dysbiosis. The use of probiotics and prebiotics is a cost-effective and widely available intervention. Intake of probiotics and prebiotics may improve the homeostasis of gut microflora and prevent frailty and unhealthy aging. However, health effects vary among probiotics and prebiotics and among individual populations. This narrative review summarizes recent evidence about the relationship between prebiotic and probiotic consumption with health outcomes in older people.

Updated review of research on the gut microbiota and their relation to depression in animals and human beings

The gut microbiota are being called the human "second brain," as they play a key role in the regulation of the central nervous system (CNS). Recent findings provide strong evidence for the presence of bidirectional communication networks between the gut microbiota and the CNS, and such crosstalk has been correlated with alterations in major depressive disorder (MDD) and other psychiatric disorders. Further, germ-free animal models have been used to investigate the effect of the microbiota on MDD and other psychiatric disorders, which have greatly expanded our knowledge of the role of the microbiota in the etiology of MDD and promoted causality studies of this psychiatric disorder and others as well. In this review, we first introduce the methodological approaches used for microbiota research and then provide an overview of current research progress on the modulatory function and composition of the gut microbiota in MDD and the therapeutic effect of probiotics that has been gained using data from human studies as well as animal experiments. Future research should focus on identification and characterization of specific bacterial strains involved in MDD with the hope of applying these findings in the prevention and treatment of MDD.

"Gut-brain axis": Review of the role of the probiotics in anxiety and depressive disorders

BACKGROUND

Depressive disorders are the leading cause of disability worldwide and together with anxiety contribute to a very high burden of disease. Therefore, improving their treatment is a significant medical research target: The role of probiotics is a topic of great interest for the current research in this field.

OBJECTIVES

To explore the current literature about the impact of probiotics on anxious and depressive symptoms.

METHODS

Scoping review following the PRISMA guidelines.

RESULTS

The selection process yielded 23 studies. Probiotics positively affected depressive symptomatology and anxiety symptoms according to 53.83% and 43.75% of the selected studies, respectively. Among the studies assessing inflammatory biomarkers, 58.31% found they were decreased after administration of probiotics.

CONCLUSION

The results emerging from the existing literature about probiotic supplementation for depression treatment are encouraging, but further research is needed considering the shortage of clinical trials on this topic and the heterogeneity of the samples analyzed.

Can probiotics, prebiotics and synbiotics improve functional outcomes for older people: a systematic review

Aim

To review current evidence on whether probiotics, prebiotics and synbiotics improve functional outcomes for older people.

Findings

There is limited evidence that probiotics might improve cognition in older people with pre-existing cognitive impairment. There is little evidence for benefit of probiotics, prebiotics and synbiotics on physical function, frailty, mood, mortality or length of hospital admission among older people, although the 18 studies identified for the review were heterogeneous and these functional outcomes were largely secondary outcomes.

Message

More robust research with larger studies, consistency of interventions and clear assessment of confounding variables (such as diet, co-morbidities and medications) is needed to evaluate the effect of probiotics, prebiotics and synbiotics on functional outcomes in an older population.

Electronic supplementary material

The online version of this article (10.1007/s41999-020-00396-x) contains supplementary material, which is available to authorized users.

Purpose

Research evaluating the effect of probiotics, prebiotics and synbiotics (PPS) on laboratory markers of health (such as immunomodulatory and microbiota changes) is growing but it is unclear whether these markers translate to improved functional outcomes in the older population. This systematic review evaluates the effect of PPS on functional outcomes in older people.

Methods

We conducted a systematic review of the effect of PPS in older adults on functional outcomes (physical strength, frailty, mood and cognition, mortality and receipt of care). Four electronic databases were searched for studies published since year 2000.

Results

Eighteen studies (including 15 RCTs) were identified. One of five studies evaluating physical function reported benefit (improved grip strength). Two analyses of one prebiotic RCT assessed frailty by different methods with mixed results. Four studies evaluated mood with no benefit reported. Six studies evaluated cognition: four reported cognitive improvement in participants with pre-existing cognitive impairment receiving probiotics. Seven studies reported mortality as a secondary outcome with a trend to reduction in only one. Five studies reported length of hospital stay but only two peri-operative studies reported shorter stays.

Conclusion

There is limited evidence that probiotics may improve cognition in older people with pre-existing cognitive impairment but no clear evidence of benefit of PPS on physical function, frailty, mood, length of hospitalisation and mortality. Larger studies with more homogenous interventions, accounting for confounding factors, such as diet, co-morbidities and medications, are required. There is currently inadequate evidence to recommend PPS use to older people in general.

PROSPERO registration number

PROSPERO registration number is CRD42020173417. Date of PROSPERO registration: 01/05/20.

Electronic supplementary material

The online version of this article (10.1007/s41999-020-00396-x) contains supplementary material, which is available to authorized users.

A Double-Blind, Randomized, Placebo-Controlled Trial of Heat-Killed Pediococcus acidilactici K15 for Prevention of Respiratory Tract Infections among Preschool Children

Although some probiotic bacteria have been reported to prevent infections in children, there are few well-designed double-blind studies. Here we evaluated the effects of a probiotic strain of lactic acid bacteria (LAB), Pediococcus acidilactici K15, on viral respiratory tract infections in preschool children. A four-month, randomized, double-blind, placebo-controlled study was performed in 172 healthy children aged 3 to 6 years. Subjects were administered dextrin alone or dextrin including heat-killed K15 (5 × 10¹⁰ bacteria). The number of febrile days was the primary outcome. The number of absent days from preschools and the influenza incidence were secondary outcomes. Secretory IgA (sIgA) concentrations in saliva were measured as an exploratory outcome. The primary and secondary outcomes were not significantly different between both groups. Analyses in children with little intake of fermented foods including LAB showed that the duration of a fever significantly decreased by K15 intake. The salivary sIgA level in the K15 group was maintained significantly higher than it was in the placebo group. The effects of K15 on preventing viral respiratory tract infections were not observed without the restriction of fermented foods intake. However, K15 supported anti-infectious immune systems in children who took less fermented foods and the maintenance of salivary sIgA levels in all subjects.

Postbiotics and paraprobiotics: From concepts to applications

In recent years, new probiotic-related concepts such as postbiotics and paraprobiotics have been used to describe non-viable microorganisms or bacterial-free extracts that may provide benefits to the host by offering bioactivities additional to probiotics. However, several aspects related to these postbiotics and paraprobiotics bioactivities remain unexplored or are poorly understood. Therefore, the aim of this work is to provide an overview of the general aspects and emerging trends of postbiotics and paraprobiotics, such as conceptualization of terms, production, characterization, bioactivities, health-promoting effects, bioengineering approaches, and applications. In vitro and in vivo studies have demonstrated that some postbiotics and paraprobiotics exhibit bioactivities such as anti-inflammatory, immunomodulatory, anti-proliferative, antioxidant, and antimicrobial. These bioactivities could be involved in health-promoting effects observed in human and clinical trials, but despite the scientific evidence available, the mechanisms of action and the signaling pathways involved have not been fully elucidated. Nevertheless, paraprobiotics and postbiotics possess valuable potential for the development of biotechnological products with functional ingredients for the nutraceutical industry.

Finding intestinal fortitude: Integrating the microbiome into a holistic view of depression mechanisms, treatment, and resilience

Depression affects at least 322 million people globally, or approximately 4.4% of the world's population. While the earnestness of researchers and clinicians to understand and treat depression is not waning, the number of individuals suffering from depression continues to increase over and above the rate of global population growth. There is a sincere need for a paradigm shift. Research in the past decade is beginning to take a more holistic approach to understanding depression etiology and treatment, integrating multiple body systems into whole-body conceptualizations of this mental health affliction. Evidence supports the hypothesis that the gut microbiome, or the collective trillions of microbes inhabiting the gastrointestinal tract, is an important factor determining both the risk of development of depression and persistence of depressive symptoms. This review discusses recent advances in both rodent and human research that explore bidirectional communication between the gut microbiome and the immune, endocrine, and central nervous systems implicated in the etiology and pathophysiology of depression. Through interactions with circulating inflammatory markers and hormones, afferent and efferent neural systems, and other, more niche, pathways, the gut microbiome can affect behavior to facilitate the development of depression, exacerbate current symptoms, or contribute to treatment and resilience. While the challenge of depression may be the direst mental health crisis of our age, new discoveries in the gut microbiome, when integrated into a holistic perspective, hold great promise for the future of positive mental health.

Postbiotics and Their Potential Applications in Early Life Nutrition and Beyond

Postbiotics are functional bioactive compounds, generated in a matrix during fermentation, which may be used to promote health. The term postbiotics can be regarded as an umbrella term for all synonyms and related terms of these microbial fermentation components. Therefore, postbiotics can include many different constituents including metabolites, short-chain fatty acids (SCFAs), microbial cell fractions, functional proteins, extracellular polysaccharides (EPS), cell lysates, teichoic acid, peptidoglycan-derived muropeptides and pili-type structures. Postbiotics is also a rather new term in the '-biotics' field. Where consensus exists for the definitions of pre- and probiotics, this is not yet the case for postbiotics. Here we propose a working definition and review currently known postbiotic compounds, their proposed mechanisms, clinical evidence and potential applications. Research to date indicates that postbiotics can have direct immunomodulatory and clinically relevant effects and evidence can be found for the use of postbiotics in healthy individuals to improve overall health and to relief symptoms in a range of diseases such as infant colic and in adults atopic dermatitis and different causes of diarrhea.

Prebiotics and probiotics for depression and anxiety: A systematic review and meta-analysis of controlled clinical trials

With growing interest in the gut microbiome, prebiotics and probiotics have received considerable attention as potential treatments for depression and anxiety. We conducted a random-effects meta-analysis of 34 controlled clinical trials evaluating the effects of prebiotics and probiotics on depression and anxiety. Prebiotics did not differ from placebo for depression (d = -.08, p = .51) or anxiety (d = .12, p = .11). Probiotics yielded small but significant effects for depression (d = -.24, p < .01) and anxiety (d = -.10, p = .03). Sample type was a moderator for probiotics and depression, with a larger effect observed for clinical/medical samples (d = -.45, p < .001) than community ones. This effect increased to medium-to-large in a preliminary analysis restricted to psychiatric samples (d = -.73, p < .001). There is general support for antidepressant and anxiolytic effects of probiotics, but the pooled effects were reduced by the paucity of trials with clinical samples. Additional randomized clinical trials with psychiatric samples are necessary fully to evaluate their therapeutic potential.

Innovative and practical conditioning beverages for public health and athletic performance: Focus on immunopotentiation by lactic acid bacteria B240

[Purpose]

Functional beverages are a protective or enhancing factor influencing not only public health but also athletic performance. The purpose of this study was to highlight the new conditioning beverage of the Lactobacillus pentosus strain b240 (B240) with electrolytes or proteins, which strengthens immune functions to improve the quality of life.

[Methods]

ISeveral related studies systematically reviews three main issues associated with conditioning beverages: (a) utilization and availability of the functional beverage; (b) significance of B240 in immune strengthening; and (c) availability and application of conditioning drinks in the daily life and sports field.

[Results]

Intake of B240 led to greater enhancements, including blood T-helper, NK cell, IgA and IgG level in conjunction with strengthen immune func¬tions. These results speculated that the practical application of B240 contained beverages on physiological health and performance.

[Conclusion]

BODYMAINTÉ, this novel conditioning beverage is expected biological utility responsible for improved sports performance as a functional drink and has potential health-related implications.

From isoniazid to psychobiotics: the gut microbiome as a new antidepressant target

An awareness of the importance of the gut-brain axis in psychiatric disorders such as depression is increasing. The gut microbiome is a key component of this axis. Gut bacteria can communicate with the brain through a variety of pathways including the hypothalamic-pituitary-adrenal axis, immune modulation, tryptophan metabolism and the production of various neuroactive compounds. Patients with depression, and other mood and anxiety disorders, show distinct compositional changes in their gut bacteria profile, raising the question about a possible aetiological role for the microbiome in these disorders. Evidence is emerging that the gut microbiome may represent a new potential antidepressant target and the term 'psychobiotic' has been coined to describe bacteria which confer mental health benefits. Gut bacteria are easily accessible and can be altered in a variety of ways including through the use of probiotics, prebiotics and dietary change. Psychobiotics containing various Lactobacillus and Bifidobacterium species have demonstrated the ability to improve mood, reduce anxiety and enhance cognitive function in both healthy populations and patient groups. This article provides an overview of the identification and development of antidepressant psychobiotics, from the preclinical evidence in the laboratory to the more recent encouraging results from human trials.

Effect of probiotic interventions on depressive symptoms: A narrative review evaluating systematic reviews

Depression is one of the most prevalent mental illnesses and is often associated with various other medical disorders. Since the 1980s, the primary pharmacological treatment has been antidepressants, but due to the recent discovery of the association between the gut microbiome and mental health, probiotics have been proposed as an adjunctive or alternate treatment. In this narrative review, we aim to provide a holistic perspective by synthesizing and evaluating existing evidence, discussing key biological mechanisms, exploring the history of probiotic use, and appreciating the influence of modern diet on mental health. Five online databases were searched for relevant studies up to December 2017. Systematic reviews that included randomized controlled trials assessing the efficacy of probiotics in the treatment of depressive symptoms were included. Seven systematic reviews met the inclusion criteria. Three of these reviews conducted meta-analyses, out of which, two concluded that probiotics improved depressive symptoms in the sample population. Out of the four reviews that conducted qualitative analysis, three reviews concluded that probiotics have the potential to be used as a treatment. Due to the differences in clinical trials, a definitive effect of probiotics on depressive symptoms cannot be concluded. Nonetheless, probiotics seem to potentially produce a significant therapeutic effect for subjects with pre-existing depressive symptoms. Further studies are warranted for definitive conclusions.

Utility of Probiotics for Maintenance or Improvement of Health Status in Older People - A Scoping Review

OBJECTIVE

To evaluate the available evidence on probiotic use in older adults from human studies.

DESIGN

systematic review.

METHODS

The databases Embase, CINAHL and Medline were searched in December of 2017 for studies in humans where probiotics were used to modify a health outcome in older people. The quality of studies was evaluated using the Critical Appraisal Skills Program (CASP) assessment tool and the Cochrane Risk of Bias Assessment tool.

PARTICIPANTS

Subjects aged over sixty years either through specified selection criteria or where the mean participant age was greater than sixty.

INTERVENTIONS

Probiotic supplements.

MEASUREMENTS

Pre-specified clinically measurable health outcomes in age related conditions.

RESULTS

1210 articles were identified. After quality assessment and selection criteria were applied, 33 articles were identified to be included for review. As these studies cover a variety of applications and used customised protocols accordingly, meta-analysis was not possible and synthesis is in narrative form.

CONCLUSIONS

A growing body of research has applied commercially available probiotic preparations across care settings for age related conditions including gut dysmotility, osteoporosis, common infectious diseases and cognitive impairment. Although methodologies vary, randomised controlled trials have reproduced results in these areas, and so warrant consideration of probiotics as a low risk adjuvant treatment for specific indications in the elderly.

Cross-species examination of single- and multi-strain probiotic treatment effects on neuropsychiatric outcomes

Interest in elucidating gut-brain-behavior mechanisms and advancing neuropsychiatric disorder treatments has led to a recent proliferation of probiotic trials. Yet, a considerable gap remains in our knowledge of probiotic efficacy across populations and experimental contexts. We conducted a cross-species examination of single- and multi-strain combinations of established probiotics. Forty-eight human (seven infant/child, thirty-six young/middle-aged adult, five older adult) and fifty-eight non-human (twenty-five rat, twenty-seven mouse, five zebrafish, one quail) investigations met the inclusion/exclusion criteria. Heterogeneity of probiotic strains, substrains, and study methodologies limited our ability to conduct meta-analyses. Human trials detected variations in anxiety, depression, or emotional regulation (single-strain 55.6%; multi-strain 50.0%) and cognition or social functioning post-probiotic intake (single-strain 25.9%; multi-strain 31.5%). For the non-human studies, single- (60.5%) and multi-strain (45.0%) combinations modified stress, anxiety, or depression behaviors in addition to altering social or cognitive performance (single-strain 57.9%; multi-strain 85.0%). Rigorous trials that confirm existing findings, investigate additional probiotic strain/substrain combinations, and test novel experimental paradigms, are necessary to develop future probiotic treatments that successfully target specific neuropsychiatric outcomes.

Effects of paraprobiotic Lactobacillus paracasei MCC1849 supplementation on symptoms of the common cold and mood states in healthy adults

We investigated the effects of paraprobiotic Lactobacillus paracasei MCC1849 (LAC-Shield™) on symptoms of the common cold and mood states in healthy young adults. A total of 241 participants were randomised to receive 1×10¹⁰ heat-killed L. paracasei MCC1849 cell powder (10LP), 3×10¹⁰ heat-killed L. paracasei MCC1849 cell powder (30LP), or placebo powder without any L. paracasei cells once daily for 12 weeks based on the incidence of the common cold in the previous year, so that the risk of the incidence was equal among the groups. The incidence and severity of common cold symptoms were rated daily in a subject diary. Salivary secretory immunoglobulin A concentrations and saliva flow rates were analysed at 0 and 6 weeks. The Profile of Mood States (POMS) was assessed using POMS 2 0, 6, and 12 weeks after the intervention. No significant differences were observed in the incidence of the common cold among the groups. In a prespecified subgroup of subjects who had the common cold in the previous year, the incidence, total number of days of symptoms, and symptom scores of the common cold significantly improved in the 10LP-intake group, and were slightly lower in the 30LP-intake group than in the placebo group. The level of deterioration in the positive mood state caused by stress was less in the MCC1849-intake group than in the placebo group. These results indicate that L. paracasei MCC1849 has the potential to improve resistance to common cold infections in susceptible subjects and maintain a desirable mood state, even under mental stress conditions. Further randomised controlled trials are needed in order to investigate the possible beneficial effects of paraprobiotic L. paracasei MCC1849 on the common cold in susceptible populations.

Effectiveness of probiotics on the occurrence of infections in older people: systematic review and meta-analysis

BACKGROUND

infectious diseases in older people are associated with higher mortality rates and probiotics have been hypothesised to reduce the occurrence of infection.

OBJECTIVES

to assess the effectiveness and safety of probiotics in the occurrence of infections in older adults in comparison to placebo.

METHODS

a systematic review and meta-analysis of randomised placebo-controlled trials were conducted on 30 December 2016 using Medline, Embase, CENTRAL, Web of Science and LILACS databases. Efficacy outcomes were: occurrence of infection, quality of life, mortality and mean duration of infection per episode. Safety outcomes were adverse events. Data were analysed using relative risk ratios with 95% confidence intervals. Relative risk ratios were pooled where more than three estimates were available.

RESULTS

fifteen articles were included, with a total of 5,916 participants with a mean age of 75.21 years. The effect of probiotics was not significantly different from that reported for placebo on the occurrence of infection, adverse events, mortality or mean duration of infection episodes (relative risk (RR) 0.90, 95% confidence interval (CI) 0.76 to 1.08; RR 1.01, 95% CI 0.91 to 1.12; RR 1.09, 95% CI 0.70 to 1.72; MD -0.35, 95% CI -1.57 to 0.87, respectively).

CONCLUSION

the current low-quality evidence does not support the use of probiotics for the reduction in the occurrence of infection in older adults, however, the safety outcomes were similar between probiotics and placebo. Further research is required to confirm these findings.PROSPERO: CRD42014013707.

A Controlled Fermented Samjunghwan Herbal Formula Ameliorates Non-alcoholic Hepatosteatosis in HepG2 Cells and OLETF Rats

Hepatosteatosis (HS), a clinical feature of fatty liver with the excessive intracellular accumulation of triglyceride in hepatocytes, is manifested by perturbation of the maintenance of liver lipid homeostasis. Samjunghwan (SJH) is an herbal formula used mostly in Korean traditional medicine that is effective against a number of metabolic diseases, including obesity. Herbal drugs, enriched with numerous bioactive substances, possess health-protective benefits. Meanwhile, fermented herbal products enriched with probiotics are known to improve metabolic processes. Additionally, current lines of evidence indicate that probiotics-derived metabolites, termed as postbiotics, produce the same beneficial effects as their precursors. Herein, the anti-HS effects of 5-weeks naturally fermented SJH (FSJH) was investigated with FSJH-mixed chow diet in vivo using Otsuka Long-Evans Tokushima Fatty (OLETF) and Long-Evans Tokushima Otsuka (LETO) rats as animal models of HS and controls, respectively. In parallel, the anti-HS effects of postbiotic-metabolites of three bacterial strains [Lactobacillus brevis (LBB), Lactococcus lactis (LCL) and Lactobacillus plantarum (LBP)] isolated from FSJH were also evaluated in vitro using the FFAs-induced HepG2 cells. Feeding OLETF rats with FSJH-diet effectively reduced body, liver, and visceral adipose tissue (VAT) weights, produced marked hypolipidemic effects on serum and hepatic lipid parameters, decreased serum AST and ALT levels, and upregulated the HMGCOR, SREBP, and ACC, and downregulated the AMPK and LDLR gene expressions levels. Additionally, exposure of FFAs-induced HepG2 cells to postbiotic metabolic media (PMM) of bacterial strains also produced marked hypolipidemic effects on intracellular lipid contents and significantly unregulated the HMGCOR, SREBP, and ACC, and downregulated the AMPK and LDLR genes expressions levels. Overall, our results indicate that FSJH enriched with fermented metabolites could be an effective anti-HS formulation.

A meta-analysis of the use of probiotics to alleviate depressive symptoms

INTRODUCTION

Some preclinical and clinical studies have demonstrated the positive impact of probiotic supplementation on depressive symptoms. This paper aims to provide an updated meta-analysis on the topic.

METHODS

Using the keywords [probiotics OR gut OR microflora OR microbiome OR bacteria OR yeast OR yoghurt OR lactobacillus OR bifidobacterium] AND [mood OR depression OR MDD OR suicide], a preliminary search on the PubMed, Ovid, Clinical Trials Register of the Cochrane Collaboration Depression, Anxiety and Neurosis Group (CCDANTR) and Cochrane Field for Complementary Medicine database yielded 917 papers published in English between 1-Jan-1960 and 1-June-2017.

RESULTS

10 clinical trials with a total of 1349 patients were reviewed, comparing the use of probiotics to placebo controls. There was no significant difference in mood between the treatment and placebo group post-intervention as the standardized mean difference (SMD) was -0.128 (95% CI -0.261 to 0.00463, P=0.059). A separate subgroup analysis of studies conducted in healthy versus depressed individuals found significant improvements in the moods of individuals with mild to moderate depressive symptoms (SMD -0.684, 95% CI -1.296 to -0.0712, P=0.029) and non-significant effects in healthy individuals (SMD -0.0999, 95% CI -0.235 to 0.0348, P=0.146).

LIMITATIONS

Inter-study discrepancies with respect to probiotic dosing, bacterial strains and strain combinations limit the comparability of current clinical trials. Furthermore, majority of existing RCTs were conducted in healthy individuals, making it difficult to extrapolate the results to depressed individuals.

CONCLUSION

Probiotic supplementation has an overall insignificant effect on mood. Future studies should be conducted on more patients with clinically diagnosed depression.

Is there a role for modified probiotics as beneficial microbes: a systematic review of the literature

Our objective was to conduct a systematic review and meta-analysis for the use of modified (heat-killed or sonicated) probiotics for the efficacy and safety to prevent and treat various diseases. Recent clinical research has focused on living strains of probiotics, but use in high-risk patients and potential adverse reactions including bacteremia has focused interest on alternatives to the use of live probiotics. We searched MEDLINE/PubMed, Embase, Cochrane Central Register of Controlled Trials, CINAHL, Alt Health Watch, Web of Science, Scopus, PubMed, from inception to February 14, 2017 for randomised controlled trials involving modified probiotic strains. The primary outcome was efficacy to prevent or treat disease and the secondary outcome was incidence of adverse events. A total of 40 trials were included (n=3,913): 14 trials (15 arms with modified probiotics and 20 control arms) for the prevention of diseases and 26 trials (29 arms with modified probiotics and 32 control arms) for treatment of various diseases. Modified microbes were compared to either placebo (44%), or the same living probiotic strain (39%) or to only standard therapies (17%). Modified microbes were not significantly more or less effective than the living probiotic in 86% of the preventive trials and 69% of the treatment trials. Modified probiotic strains were significantly more effective in 15% of the treatment trials. Incidence rates of adverse events were similar for modified and living probiotics and other control groups, but many trials did not collect adequate safety data. Although several types of modified probiotics showed significant efficacy over living strains of probiotics, firm conclusions could not be reached due to the limited number of trials using the same type of modified microbe (strain, daily dose and duration) for a specific disease indication. Further research may illuminate other strains of modified probiotics that may have potential as clinical biotherapeutics.

RNA and a cell wall component of Enterococcus faecalis IC-1 are required for phagocytosis and interleukin 12 production by the mouse macrophage cell line J774.1

Enterococcus faecalis is a resident lactic acid bacterium in the human intestine. Its immunostimulatory action was reported to be enhanced by heat sterilization. To investigate its beneficial actions, we evaluated the ability of 10 E. faecalis strains to induce interleukin-12 (IL-12) production in a mouse macrophage cell line, J774.1 and found that the strain, E. faecalis IC-1, had a potent IL-12-inducing ability. Furthermore, we investigated the underlying mechanism by treating IC-1 cells with RNase or lysozyme. Its activity almost disappeared and an antagonist of Toll-like receptor (TLR) 7 inhibited this activity. Moreover, lysozyme-treated IC-1 bacteria were not phagocytized by J774.1 cells, and did not induce IL-12 production. Based on our results, we propose that macrophages recognize the cell wall components of IC-1, leading to phagocytosis. The IC-1 RNA is then recognized by TLR7, which induces the production of IL-12.

Pilot, double-blind, randomized, placebo-controlled clinical trial of the supplement food Nyaditum resae® in adults with or without latent TB infection: Safety and immunogenicity

BACKGROUND

Nyaditum resae® (NR) is a galenic preparation of heat-killed Mycobacterium manresensis, a new species of the fortuitum complex, that is found in drinkable water, and that has demonstrated to protect against the development of active TB in a murine experimental model that develop human-like lesions.

METHODS

Double-blind, randomized, placebo-controlled Clinical Trial (51 volunteers included). Two different doses of NR and a placebo were tested, the randomization was stratified by Latent Tuberculosis Infection (LTBI)-positive (n = 21) and LTBI-negative subjects (n = 30). Each subject received 14 drinkable daily doses for 2 weeks.

RESULTS

All patients completed the study. The 46.3% of the overall reported adverse events (AE) were considered related to the investigational treatment. None of them were severe (94% were mild and 6% moderate). No statistical differences were found when comparing the median number of AE between the placebo group and both treatment groups. The most common AE reported were gastrointestinal events, most frequently mild abdominal pain and increase in stool frequency. Regarding the immunogenic response, both LTBI-negative and LTBI-positive volunteers treated with NR experienced a global increase on the Treg response, showed both in the population of CD25+CD39-, mainly effector Treg cells, or CD25+CD39+ memory PPD-specific Treg cells.

CONCLUSION

This clinical trial demonstrates an excellent tolerability profile of NR linked to a significant increase in the population of specific effector and memory Tregs in the groups treated with NR in both LTBI-positive and negative subjects. NR shows a promising profile to be used to reduce the risk of active TB.

Respiratory Antiviral Immunity and Immunobiotics: Beneficial Effects on Inflammation-Coagulation Interaction during Influenza Virus Infection

Influenza virus (IFV) is a major respiratory pathogen of global importance, and the cause of a high degree of morbidity and mortality, especially in high-risk populations such as infants, elderly, and immunocompromised hosts. Given its high capacity to change antigenically, acquired immunity is often not effective to limit IFV infection and therefore vaccination must be constantly redesigned to achieve effective protection. Improvement of respiratory and systemic innate immune mechanisms has been proposed to reduce the incidence and severity of IFV disease. In the last decade, several research works have demonstrated that microbes with the capacity to modulate the mucosal immune system (immunobiotics) are a potential alternative to beneficially modulate the outcome of IFV infection. This review provides an update of the current status on the modulation of respiratory immunity by orally and nasally administered immunobiotics, and their beneficial impact on IFV clearance and inflammatory-mediated lung tissue damage. In particular, we describe the research of our group that investigated the influence of immunobiotics on inflammation–coagulation interactions during IFV infection. Studies have clearly demonstrated that hostile inflammation is accompanied by dysfunctional coagulation in respiratory IFV disease, and our investigations have proved that some immunobiotic strains are able to reduce viral disease severity through their capacity to modulate the immune-coagulative responses in the respiratory tract.

A review of dose-responses of probiotics in human studies

The probiotic definition requires the administration of an 'adequate amount' in order to obtain a health benefit. What that amount should be is not indicated. Here, an overview is given of studies that investigated the dose-response relation of probiotics in human interventions. Studies were divided in; meta-analyses, meta-analyses on specific probiotic strains, and studies testing two or more doses of a probiotic (combination) in the same study. Meta-analyses on the effect of probiotics on antibiotic associated diarrhoea (AAD) suggest a dose-response effect; for Clostridium difficile-associated diarrhoea on the other hand no dose-response was observed. For other end-points; such as necrotising enterocolitis, prevention of atopic dermatitis and slow intestinal transit, no dose-response relation was identified in meta-analyses. For prophylaxis in colorectal cancer and relief of irritable bowel syndrome, no dose-response relation was determined. However, for blood pressure, a meta-analysis observed that higher doses (greater than 10¹¹ cfu) were more effective than lower doses. Meta-analyses of specific strains suggest a break-point for effectiveness of Lactobacillus rhamnosus GG in the treatment of acute gastroenteritis in children; no dose-response was observed for two other probiotics assessed. Studies comparing two or more doses indicate that faecal recovery and risk reduction of AAD follow a positive dose-response relationship. Other end-points such as immune markers, general health, and bowel function did not exhibit clear dose-response relations. For AAD, the findings are very compelling; both meta-analyses and dedicated dose-response studies observe a positive correlation between dose and AAD risk. These findings do not allow for extrapolation, but suggest that studying higher doses for this end-point would be worthwhile. The lack of a clear dose-response for other end-points, does not mean it does not exist; present data does just not allow drawing any conclusions.

Effect of Probiotics on Depression: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

It has been reported that gut probiotics play a major role in the bidirectional communication between the gut and the brain. Probiotics may be essential to people with depression, which remains a global health challenge, as depression is a metabolic brain disorder. However, the efficacy of probiotics for depression is controversial. This study aimed to systematically review the existing evidence on the effect of probiotics-based interventions on depression. Randomized, controlled trials, identified through screening multiple databases and grey literature, were included in the meta-analysis. The meta-analysis was performed using Review Manager 5.3 software using a fixed-effects model. The meta-analysis showed that probiotics significantly decreased the depression scale score (MD (depressive disorder) = −0.30, 95% CI (−0.51–−0.09), p = 0.005) in the subjects. Probiotics had an effect on both the healthy population (MD = −0.25, 95% CI (−0.47–−0.03), p = 0.03) and patients with major depressive disorder (MDD) (MD = −0.73, 95% CI (−1.37–−0.09), p = 0.03). Probiotics had an effect on the population aged under 60 (MD = −0.43, 95% CI (−0.72–−0.13), p = 0.005), while it had no effect on people aged over 65 (MD = −0.18, 95% CI (−0.47–0.11), p = 0.22). This is the first systematic review and meta-analysis with the goal of determining the effect of probiotics on depression. We found that probiotics were associated with a significant reduction in depression, underscoring the need for additional research on this potential preventive strategy for depression.

The effects of non-viable Lactobacillus on immune function in the elderly: a randomised, double-blind, placebo-controlled study

Forty-two participants in two nursing homes who were ≥65 years of age were randomised to receive a jelly containing 10 billion heat-killed Lactobacillus paracasei MCC1849 cells (LP group) or a placebo jelly without lactobacilli (placebo group) for 6 weeks. Three weeks after beginning jelly intake, all subjects received an influenza vaccination (A/H1N1, A/H2N3 and B). Blood samples were collected before and after the treatment period. There were no significant differences in immune parameters, including in antibody responses against the vaccination, between the groups. In the subgroup of the oldest old, defined as ≥85 years of age (n = 27), the antibody responses to the A/H1N1 and B antigens, which were impaired in the placebo group, were improved in the LP group. No significant effects of non-viable L. paracasei MCC1849 were observed in the elderly. A possible beneficial effect in the oldest old should be explored in further large-scale studies.

Mechanisms and therapeutic effectiveness of lactobacilli

The gut microbiome is not a silent ecosystem but exerts several physiological and immunological functions. For many decades, lactobacilli have been used as an effective therapy for treatment of several pathological conditions displaying an overall positive safety profile. This review summarises the mechanisms and clinical evidence supporting therapeutic efficacy of lactobacilli. We searched Pubmed/Medline using the keyword ‘Lactobacillus’. Selected papers from 1950 to 2015 were chosen on the basis of their content. Relevant clinical and experimental articles using lactobacilli as therapeutic agents have been included. Applications of lactobacilli include kidney support for renal insufficiency, pancreas health, management of metabolic imbalance, and cancer treatment and prevention. In vitro and in vivo investigations have shown that prolonged lactobacilli administration induces qualitative and quantitative modifications in the human gastrointestinal microbial ecosystem with encouraging perspectives in counteracting pathology-associated physiological and immunological changes. Few studies have highlighted the risk of translocation with subsequent sepsis and bacteraemia following probiotic administration but there is still a lack of investigations on the dose effect of these compounds. Great care is thus required in the choice of the proper Lactobacillus species, their genetic stability and the translocation risk, mainly related to inflammatory disease-induced gut mucosa enhanced permeability. Finally, we need to determine the adequate amount of bacteria to be delivered in order to achieve the best clinical efficacy decreasing the risk of side effects.

Supplementary heat-killed Lactobacillus reuteri GMNL-263 ameliorates hyperlipidaemic and cardiac apoptosis in high-fat diet-fed hamsters to maintain cardiovascular function

Obesity and hyperlipidaemia increase the risk of CVD. Some strains of probiotics have been suggested to have potential applications in cardiovascular health by lowering serum LDL-cholesterol. In this work, high-fat diet-induced hyperlipidaemia in hamsters was treated with different doses (5×108 and 2·5×109 cells/kg per d) of heat-killed Lactobacillus reuteri GMNL-263 (Lr263) by oral gavage for 8 weeks. The serum lipid profile analysis showed that LDL-cholesterol and plasma malondialdehyde (P-MDA) were reduced in the GMNL-263 5×108 cells/kg per d treatment group. Total cholesterol and P-MDA were reduced in the GMNL-263 2·5×109 cells/kg per d treatment group. In terms of heart function, the GMNL-263 2·5×109 cells/kg per d treatments improved the ejection fraction from 85·71 to 91·81 % and fractional shortening from 46·93 to 57·92 % in the high-fat diet-fed hamster hearts. Moreover, the GMNL-263-treated, high-fat diet-fed hamster hearts exhibited reduced Fas-induced myocardial apoptosis and a reactivated IGF1R/PI3K/Akt cell survival pathway. Interestingly, the GMNL-263 treatments also enhanced the heat-shock protein 27 expression in a dose-dependent manner, but the mechanism for this increase remains unclear. In conclusion, supplementary heat-killed L. reuteri GMNL-263 can slightly reduce serum cholesterol. The anti-hyperlipidaemia effects of GMNL-263 may reactivate the IGF1R/PI3K/Akt cell survival pathway and reduce Fas-induced myocardial apoptosis in high-fat diet-fed hamster hearts.