Effects of a probiotic treatment (Enterococcus faecalis) and open-label placebo on symptoms of allergic rhinitis: study protocol for a randomised controlled trial

A randomized controlled trial of effects of open-label placebo compared to double-blind placebo and treatment-as-usual on symptoms of allergic rhinitis

Placebo effects are known for numerous clinical symptoms. Until recently, deception of placebos was thought to be essential for placebo effects, but intriguing new studies suggest that even placebos without concealment (open-label placebos) may help patients with various clinical disorders. Most of those studies compared open-label placebo treatments with no treatment conditions (or treatment "as usual"). Given that open-label placebo studies obviously cannot be blinded, additional control studies are important to assess the efficacy of open-label placebos. The current study aimed to fil this gap by comparing open-label with conventional double-blind placebos and treatment as usual. Patients with seasonal allergic rhinitis were randomly divided in different groups. The first group received open-label placebos, the second double-blind placebos, and the third was treated as usual. After 4 weeks, results demonstrated that open-label placebos improved allergic symptoms more than treatment-as-usual and even more as double-blind placebos. In addition, we observed that allergic symptoms in general (and also the open-label placebo effects) were reduced by the Covid-19 pandemic. The results suggest that seasonal allergic symptoms may be relieved by open-label placebos. We discuss these results by addressing possible different mechanisms of open-label and conventionally concealed placebo treatments.

Assessment of a Multispecies Probiotic Supplement for Relief of Seasonal Allergic Rhinitis: A Randomized Double-Blind Placebo-Controlled Trial

Background: Early phase clinical research provided initial support for the use of a multispecies probiotic supplement to improve quality of life (QoL) in adults with seasonal allergic rhinitis (AR) and reduce the use of AR symptom relieving medication. This study aimed to confirm these early phase findings in a double-blind randomized placebo-controlled trial. Methods: Individuals, aged 18-65 years, with a minimum 2-year history of AR, moderate-to-severe AR symptoms, and a positive radio-allergosorbent test to Bermuda (Couch) Grass were randomized to receive either a multispecies probiotic supplement (total colony-forming units 4 × 10⁹/day) or placebo twice daily for 8 weeks. A mini-rhinoconjunctivitis quality of life questionnaire (mRQLQ) scale was administered at screening, days 0, 28, and 56. The proportion of participants with a >0.7 improvement in mRQLQ was the primary outcome. Participants also completed a daily symptom and medication diary during the supplementation period. Results: There were 165 participants randomized, with 142 included in the primary outcome analysis. The percentage of participants meeting the threshold for a clinically meaningful reduction in the mRQLQ from days 0 to 56 was not significantly different between groups (61% vs. 62%, p = 0.90). However, 76 participants had a clinically meaningful improvement in QoL (decrease in mRQLQ >0.7) prior to the start of supplementation (screening to day 0). Conclusion: Changes in self-reported QoL and other disease severity metrics between screening and the start of supplementation limited the ability to discern an effect of supplementation and highlight the need for adaptive clinical trial designs in allergy research. Clinical Trial Registration: The trial was registered with the Australia and New Zealand Clinical Trials Registry (ACTRN12619001319167).

Research Advances in the Treatment of Allergic Rhinitis by Probiotics

Allergic rhinitis (AR) impairs the quality of life of patients and reduces the efficiency of social work, it is an increasingly serious public medical and economic problem in the world. Conventional anti-allergic drugs for the treatment of allergic rhinitis (AR) can cause certain side effects, which limit the quality of life of patients. Therefore, it makes sense to look for other forms of treatment. Several studies in recent years have shown that probiotics have shown anti-allergic effects in various mouse and human studies. For example, the application of certain probiotic strains can effectively relieve the typical nasal and ocular symptoms of allergic rhinitis in children and adults, thereby improving the quality of life and work efficiency. At the same time, previous studies in humans and mice have found that probiotics can produce multiple effects, such as reduction of Th2 cell inflammatory factors and/or increase of Th1 cell inflammatory factors, changes in allergy-related immunoglobulins and cell migration, regulate Th1/Th2 balance or restore intestinal microbiota disturbance. For patients with limited activity or allergic rhinitis with more attacks and longer attack duration, oral probiotics have positive effects. The efficacy of probiotics in the prevention and treatment of allergic rhinitis is remarkable, but its specific mechanism needs further study. This review summarizes the research progress of probiotics in the treatment of allergic rhinitis in recent years.

Microbiome profiling of nasal extracellular vesicles in patients with allergic rhinitis

Background

Methods

Results

Conclusion

The efficacy of probiotics in the management of intra-oral halitosis: a systematic review

OBJECTIVES

To evaluate the efficacy of probiotics in reducing halitosis of dental origin.

METHODS

MEDLINE, EMBASE, and CENTRAL were searched up to and including June 2020. Randomised placebo-controlled, double-blinded clinical trials in systemically healthy adult patients who were given any form of probiotics to manage halitosis of dental origin were included. Primary outcome measures were organoleptic scores and volatile sulphur concentration levels. Secondary outcome measures were microbiologic parameters and quality of life (QOL).

RESULTS

Of the 301 potentially relevant articles, eight articles were selected for the review. The risk of bias assessment showed that two studies were of low risk of bias, four studies had some concerns, and two studies had a high risk of bias. The beneficial effect of probiotics could neither be confirmed in periodontally treated patients administered with up to 8 weeks of probiotics, nor in periodontitis patients who received both non-surgical periodontal therapy and adjunctive probiotics up to 90 days. Microbiological findings 1 month after probiotics administration and QOL measures showed no significant differences compared to control. Considerable heterogeneity was observed among probiotic administration protocols.

CONCLUSIONS

The available evidence suggests no convincing benefit for the use of probiotics in the management of halitosis. Standardised protocols on recruitment of halitosis subjects and organoleptic measurements are required for future studies on probiotics as an intervention.

CLINICAL RELEVANCE

The lack of well-conducted studies with a low risk of bias precludes any clinical recommendation. Further research is needed to verify the efficacy of probiotics in the management of intra-oral halitosis.

Review of probiotic use in otolaryngology

OBJECTIVE

Probiotics have garnered considerable attention as an intervention for various conditions common to otolaryngology. The purpose of this review is to evaluate the current literature to offer recommendations about the safety and efficacy of probiotic management in otolaryngologic conditions.

STUDY DESIGN

Narrative review.

METHODS

PubMed and Google Scholar were queried using pertinent keywords to retrieve relevant studies with particular focus in the recent 5 years. All abstracts were assessed and studies, reviews and meta-analyses achieving evaluation of probiotic therapies or characterization of microbiome changes were included for further review. Studies were categorized by condition or anatomic region across various subspecialties. Key data parameters were extracted and evaluated across studies and treatment types.

RESULTS

Strong evidence exists for the use probiotic agents to improve symptoms for allergic rhinitis, chronic rhinosinusitis and certain dental conditions. Despite promising results, further investigation is needed to evaluate and optimize probiotic delivery for mitigating otitis media, oropharyngeal inflammation and upper respiratory tract infections. Preclinical studies suggest that probiotics may potentially offer benefit for voice prosthesis maintenance, wound healing and mitigation of oral dysplasia.

CONCLUSION

Probiotic therapies may offer clinical benefit in a variety of contexts within the field of otolaryngology, especially for short-term relief of certain inflammatory conditions of the oral cavity, auditory and nasal cavities. Further investigation is warranted for evaluation of long-term outcomes and pathogenic deterrence.

Effects of open-label placebos on test performance and psychological well-being in healthy medical students: a randomized controlled trial

Psychological distress is prevalent in students and can predispose to psychiatric disorders. Recent findings indicate that distress might be linked to impaired cognitive performance in students. Experimental findings in healthy participants suggest that placebo interventions can improve cognition. However, whether non-deceptive (i.e., open-label, OLP) placebos can enhance cognitive function and emotional well-being is unclear. Using a randomized-controlled design we demonstrate a positive impact of OLP on subjective well-being (i.e., stress, fatigue, and confusion) after a 21-day OLP application in healthy students during midterm exams. OLP did not improve test performance, but, within the OLP group, test performance was positively correlated with measures of general belief in the benefit of medication. These results show that OLP can counteract negative effects of acute stress on psychological well-being and might improve cognitive performance if supported by positive treatment expectations. Additionally, our findings in healthy volunteers warrant further investigation in exploring the potential of OLP in reducing stress-related psychological effects in patients. The trial was preregistered at the German Clinical Trials Register on December 20, 2017 (DRKS00013557).

Placebo Responses and Placebo Effects in Functional Gastrointestinal Disorders

Much has been written about the placebo effects in functional gastrointestinal disorders (FGD), especially in irritable bowel syndrome (IBS), driven by the early hypothesis that in randomized controlled trials (RCTs) of IBS, the placebo effect might be specifically high and thus, corrupts the efficacy of novel drugs developed for this condition. This narrative review is based on a specific search method, a database (www.jips.online) developed since 2004 containing more than 4,500 papers (data papers, meta-analyses, systematic reviews, reviews) pertinent to the topic placebo effects/placebo response. Three central questions-deducted from the body of current literature-are addressed to explore the evidence behind this hypothesis: What is the size placebo effect in FGD, especially in IBS, and is it different from the placebo effect seen in other gastrointestinal disorders? Is the placebo effect in FGD different from other functional, non-intestinal disorders, e.g. in other pain syndromes? Is the placebo effect in FGD related to placebo effects seen in psychiatry, e.g. in depression, anxiety disorders, and alike? Following this discussion, a fourth question is raised as the result of the three: What are the consequences of this for future drug trials in FGD? In summary it is concluded that, contrary to common belief and discussion, the placebo effect seen in RCT in FGD is not specifically high and extraordinary as compared to other comparable (i.e. functional) disorders. It shares less than expected commonalities with the placebo effect in psychiatry, and very few predictors have yet been identified that determine its effect size, especially some that are driven by design features of the studies. Current practice of RCT in IBS seems to limit and control the placebo effect quite well, and future trial practice, e.g. head-to-head trial, still offers options to maintain this control, even in the absence of placebos used.

The mechanisms and safety of probiotics against toxigenic clostridium difficile

INTRODUCTION

Toxigenic Clostridium difficile (C. difficile) is the main cause of antibiotic-associated diarrhea and can induce pseudomembranous colitis and infrequent toxic megacolon, which are potentially fatal. The standard antibiotic therapy for C. difficile infection (CDI) is limited by antibiotics' broad spectrum and further disruptive effects on indigenous microbiota. Probiotics may offer a prospective and alternative strategy for the prevention and treatment of CDI.

AREAS COVERED

In this article, the mechanisms implying the probiotic effect against C. difficile and the safety profile highlighting the patient groups with inappropriate application of probiotics were reviewed from 2015 to 2020.

EXPERT OPINION

Although many strains with ability against C. difficile have been reported, the usage of probiotics for CDI prevention and/or treatment is scarce since the number of clinical trials is not sufficient to prove probiotics' efficacy and safety in CDI treatment, especially for premature infant and immunocompromised patient. Especially, there are few well-defined clinical studies supporting safety of probiotics for CDI. A few strains from Lactobacillus and Saccharomyces genus have been studied more extensively than other probiotic strains through clinical trials for CDI. Thus, more clinical intervention studies regarding the benefit and the comprehensive safety assessments of probiotics for CDI are needed.