Clinical efficacy of a topical lactic acid bacterial microbiome in chronic rhinosinusitis: A randomized controlled trial

Nasal Rinsing with Probiotics-Microbiome Evaluation in Patients with Inflammatory Diseases of the Nasal Mucosa

Background/Objectives: The evidence regarding the efficacy of probiotics in chronic rhinosinusitis (CRS) is very limited, prompting the EPOS2020 steering group to advise against their use in CRS treatment. Therefore, further research to evaluate the impact of probiotics on microbial communities is particularly important. This study aimed to assess the influence of probiotic nasal rinses on nasal microbiota profiles in patients with primary CRS, granulomatosis with polyangiitis (GPA), and nasal septal perforation (NSP) using 16S rRNA sequencing. Methods: Thirty-six patients with nasal mucosal diseases, including sixteen with primary CRS, eleven with GPA, and nine with NSP, were randomly assigned to either a study group receiving nasal rinses with probiotics containing Lactobacillus plantarum and Bifidobacterium animalis, or a control group using nasal rinses with saline. Metagenomic analysis targeting the V3-V4 hypervariable region of the 16S rRNA gene was performed to characterize bacterial and archaeal populations. Results: At the genus level, the most abundant co-colonizers included Staphylococcus, Streptococcus, and Haemophilus. After one month of probiotic rinsing, a decrease in abundance of the genera Finegoldia (p = 0.010), Haemophilus (p = 0.020), Streptococcus (p = 0.027), Staphylococcus (p = 0.033), Micrococcus (p = 0.035), Corynebacterium (p = 0.049), Gemella (p = 0.055), Rubrobacter (p = 0.055), and Pseudonocardia (p = 0.058) was observed. Conversely, the abundance of probiotic species Lactobacillus plantarum and Bifidobacterium animalis increased. Moreover, increases in the genera Dolosigranulum and Stenotrophomonas were observed, although they did not reach statistical significance. Conclusions: Probiotic nasal rinses may contribute to restoring microbial homeostasis by reducing genera associated with inflammatory dysbiosis in nasal inflammatory diseases, warranting further research on their clinical benefits.

Gut microbiota dysbiosis and its impact on asthma and other lung diseases: potential therapeutic approaches

The emerging field of gut-lung axis research has revealed a complex interplay between the gut microbiota and respiratory health, particularly in asthma. This review comprehensively explored the intricate relationship between these two systems, focusing on their influence on immune responses, inflammation, and the pathogenesis of respiratory diseases. Recent studies have demonstrated that gut microbiota dysbiosis can contribute to asthma onset and exacerbation, prompting investigations into therapeutic strategies to correct this imbalance. Probiotics and prebiotics, known for their ability to modulate gut microbial compositions, were discussed as potential interventions to restore immune homeostasis. The impact of antibiotics and metabolites, including short-chain fatty acids produced by the gut microbiota, on immune regulation was examined. Fecal microbiota transplantation has shown promise in various diseases, but its role in respiratory disorders is not established. Innovative approaches, including mucus transplants, inhaled probiotics, and microencapsulation strategies, have been proposed as novel therapeutic avenues. Despite challenges, including the sophisticated adaptability of microbial communities and the need for mechanistic clarity, the potential for microbiota-based interventions is considerable. Collaboration between researchers, clinicians, and other experts is essential to unravel the complexities of the gut-lung axis, paving a way for innovative strategies that could transform the management of respiratory diseases.

The role of airways microbiota on local and systemic diseases: a rationale for probiotics delivery to the respiratory tract

INTRODUCTION

Recent discoveries in the field of lung microbiota have enabled the investigation of new therapeutic interventions involving the use of inhaled probiotics.

AREAS COVERED

This review provides an overview of what is known about the correlation between airway dysbiosis and the development of local and systemic diseases, and how this knowledge can be exploited for therapeutic interventions. In particular, the review focused on attempts to formulate probiotics that can be deposited directly on the airways.

EXPERT OPINION

Despite considerable progress since the emergence of respiratory microbiota restoration as a new research field, numerous clinical implications and benefits remain to be determined. In the case of local diseases, once the pathophysiology is understood, manipulating the lung microbiota through probiotic administration is an approach that can be exploited. In contrast, the effect of pulmonary dysbiosis on systemic diseases remains to be clarified; however, this approach could represent a turning point in their treatment.

Environmental exposures, the oral-lung axis and respiratory health: The airway microbiome goes on stage for the personalized management of human lung function

The human respiratory system is constantly exposed to environmental stimuli, sometimes including toxicants, which can trigger dysregulated lung immune responses that lead to respiratory symptoms, impaired lung function and airway diseases. Evidence supports that the microbiome in the lungs has an indispensable role in respiratory health and disease, acting as a local gatekeeper that mediates the interaction between the environmental cues and respiratory health. Moreover, the microbiome in the lungs is intimately intertwined with the oral microbiome through the oral-lung axis. Here, we discuss the intricate three-way relationship between (i) cigarette smoking, which has strong effects on the microbial community structure of the lung; (ii) microbiome dysbiosis and disease in the oral cavity; and (iii) microbiome dysbiosis in the lung and its causal role in patients suffering chronic obstructive pulmonary disease (COPD), a leading cause of morbidity and mortality worldwide. We highlight exciting outcomes arising from recently established interactions in the airway between environmental exposures, microbiome, metabolites-functional attributes and the host, as well as how these associations have the potential to predict the respiratory health status of the host through an airway microbiome health index. For completion, we argue that incorporating (synthetic) microbial community ecology in our contemporary understanding of lung disease presents challenges and also rises novel opportunities to exploit the oral-lung axis and its microbiome towards innovative airway disease diagnostics, prognostics, patient stratification and microbiota-targeted clinical interventions in the context of current therapies.

The placebo effect in randomized-controlled trials of medical treatments for chronic rhinosinusitis: A systematic review and meta-analysis

BACKGROUND

The placebo effect observed in clinical trials evaluating medical treatments for chronic rhinosinusitis (CRS) is not well understood. This systematic review and meta-analysis sought to characterize the placebo effect present within CRS outcomes.

METHODS

A systematic review of PubMed, Scopus, and Cumulated Index in Nursing and Allied Health Nursing (CINAHL) was performed. Randomized controlled trials (RCTs) evaluating medical treatments for CRS versus placebo were included. We assessed patient-reported (sino-nasal outcome test 22 [SNOT-22], nasal obstruction, sense of smell, nasal obstruction visual analogue score [VAS], sense of smell VAS, anterior rhinorrhea, and postnasal drip) and objective (Lund-Mackay Computed tomography (CT) score, peak nasal inspiratory flow [PNIF], nasal polyp scores, 40-item Smell Identification Test, serum IgE, and blood eosinophil levels) outcomes.

RESULTS

Twenty-one RCTs were included, comprising 1437 patients (mean age 49.2 years). Biologics were the most common treatment investigated (n = 9). Eleven studies administered background steroids along with placebo. Following placebo administration, multiple patient-reported outcomes significantly decreased, including SNOT-22 (mean difference -9.49, 95% confidence interval [CI] [-11.26, -7.73]), nasal obstruction (-0.33 [-0.54, -0.13]), sense of smell (-0.22 [-0.33, -0.11]), nasal obstruction VAS (-2.47 [-2.87, -2.06]), and loss of smell VAS (-2.31 [-4.14, -0.47]) scores. For objective measures, significant changes occurred in Lund-Mackay CT score (-0.82, [-1.48, -0.16]) and PNIF (4.70, [4.76, 24.64]) with placebo. Placebo arms had the greatest impact when no background medications were used.

CONCLUSIONS

Placebo treatments have a statistically and potentially clinically significant effect on patient-reported and some objective CRS outcomes. Further investigation is required to fully understand placebo effect, which could improve assessment of RCTs and impact patient care.

Emerging Therapies in the Medical Management of Allergic Fungal Rhinosinusitis

A non-invasive type of chronic sinusitis named allergic fungal rhinosinusitis (AFRS), which is a variant of allergic bronchopulmonary aspergillosis with nasal obstruction, was first described in 1976. The goal of this article was to provide an overview of various treatment approaches and how they can be used to control AFRS. Since this is an inflammatory disease rather than an invasive fungal infection, the treatment tries to modulate inflammation and reduce disease burden. A comprehensive treatment strategy must incorporate medicinal, surgical, biological, and immunological techniques. Owing to the chronic nature of allergic fungal rhinosinusitis and its high propensity for flare-ups and recurrence, multiple procedures are frequently required. The most likely method of establishing a long-term disease control for AFRS is a comprehensive management strategy that integrates medical, surgical, and immunological care. However, there are still disagreements regarding the exact combinations. In this review, we have mentioned different modalities in the management of AFRS, such as monoclonal antibodies, probiotic Manuka honey, and aPDT among others, some of which are promising but require further research.

Positioning the preventive potential of microbiome treatments for cystic fibrosis in the context of current therapies

Antibiotics and cystic fibrosis transmembrane conductance regulator (CFTR) modulators play a pivotal role in cystic fibrosis (CF) treatment, but both have limitations. Antibiotics are linked to antibiotic resistance and disruption of the airway microbiome, while CFTR modulators are not widely accessible, and structural lung damage and pathogen overgrowth still occur. Complementary strategies that can beneficially modulate the airway microbiome in a preventive way are highly needed. This could be mediated via oral probiotics, which have shown some improvement of lung function and reduction of airway infections and exacerbations, as a cost-effective approach. However, recent data suggest that specific and locally administered probiotics in the respiratory tract might be a more targeted approach to prevent pathogen outgrowth in the lower airways. This review aims to summarize the current knowledge on the CF airway microbiome and possibilities of microbiome treatments to prevent bacterial and/or viral infections and position them in the context of current CF therapies.

Role of probiotics in chronic rhinosinusitis: a systematic review of randomised, controlled trials

OBJECTIVE

This review evaluated the safety profile and efficacy of probiotics in chronic rhinosinusitis and was registered with Prospero (Centre for Reviews and Dissemination number: 42020193529).

METHOD

Literature databases were searched through inception to August 2022. Randomised, controlled trials exploring adjunctive probiotics in adult chronic rhinosinusitis patients were included. From 948 records screened, 4 randomised, controlled trials were included.

RESULTS

Probiotics-associated adverse effects comprised epistaxis and abdominal pain. No reduction in Sino-Nasal Outcome Test values before 4 weeks (p = 0.58) or beyond 8 weeks (p = 0.08) of treatment or reduction of severe symptom frequency (p = 0.75) was observed. Symptom relapse in probiotic-treated patients was significantly lower across all timepoints (p = 0.045). Lower sinusitis relapse risks during treatment (risk ratio = 0.49; p = 0.019) and 8 months post-treatment (risk ratio = 0.56, p = 0.013) were observed. Probiotics demonstrated potential in improving Sino-Nasal Outcome Test symptom subscales, including sleep, psychological and rhinology subscales.

CONCLUSION

The optimal mode of probiotic administration, treatment duration and target patient subgroups requires further study to evaluate the utility of probiotics.

The Effect of Corticosteroids on Sinus Microbiota in Chronic Rhinosinusitis Patients with Nasal Polyposis

BACKGROUND

Chronic rhinosinusitis with nasal polyposis (CRSwNP) is a multifactorial disease with no known single cause, but it is thought that bacteria play a role in the disease process.

OBJECTIVE

This pilot study aims to assess the longitudinal effect of corticosteroid therapy on sinus microbiota in chronic rhinosinusitis patients with nasal polyposis (CRSwNP).

METHODS

A longitudinal prospective case-control study was done on patients with CRSwNP and healthy controls. Patients with CRSwNP were randomly allocated to a corticosteroids and antibiotics treatment group (CRSwNP-SA) or a corticosteroid-only treatment group (CRSwNP-S). Data were collected at three-time points (before treatment, 1, and 3 months after treatment). Specimens were cultured and matrix-assisted laser desorption ionization-time of flight (MALDI-TOF) mass spectrometry (MS) was used as a bacterial detection method.

RESULTS

Data from 29 patients with CRSwNP (16 CRSwNP-SA and 13 CRSwNP-S) was compared to 15 healthy subjects. Patients reported significant symptom improvement initially (1 month), but not in the long-term (3 months). This result was found in both treatment groups, whether or not antibiotics were used. After 3 months from treatment, the prevalence of Corynebacterium genera tended to increase in the CRSwNP-SA, while Staphylococcus and Gram-negative genera (Pseudomonas) tended to increase in the CRSwNP-S. Smoking, aspirin sensitivity, and previous endoscopic sinus surgery were found to be co-factors significantly associated with the response to systemic corticosteroid therapy.

CONCLUSION

In this pilot study, both treatment options were effective to improve symptoms in the short-term but not in the long-term, and were not linked to any clear sinus microbiota response. As a result, this study supports the avoidance of systemic antibiotics without evidence of active infection.

Characterization of Lactic Acid Bacteria Strains Isolated from Algerian Honeybee and Honey and Exploration of Their Potential Probiotic and Functional Features for Human Use

Using culture enrichment methods, 100 strains of bacilli of lactic acid bacteria (LAB) were isolated from honeybee Apis mellifera intermissa and fresh honey, collected from apiaries located in the north-east of Algeria. Amongst all of the isolated LAB, 19 selected strains were closely affiliated to four species-Fructobacillus fructosus (10), Apilactobacillus kunkeei (5), Lactobacillus kimbladii and/or Lactobacillus kullabergensis (4)-using phylogenetic and phenotypic approaches. The in vitro probiotic characteristics (simulated gastrointestinal fluids tolerance, autoaggregation and hydrophobicity abilities, antimicrobial activity and cholesterol reduction) and safety properties (hemolytic activity, antibiotic resistance and absence of biogenic amines) were evaluated. The results indicated that some strains showed promising potential probiotic properties. In addition, neither hemolytic activity nor biogenic amines were produced. The carbohydrate fermentation test (API 50 CHL) revealed that the strains could efficiently use a broad range of carbohydrates; additionally, four strains belonging to Apilactobacillus kunkeei and Fructobacillus fructosus were found to be exopolysaccharides (EPS) producers. This study demonstrates the honeybee Apis mellifera intermissa and one of her products as a reservoir for novel LAB with potential probiotic features, suggesting suitability for promoting host health.

Pathogenesis of Nasal Polyposis: Current Trends

Chronic Rhinosinusitis (CRS) is characterized by edema of the sub-epithelial layers, but, only specific types of CRS are developing polyps. Nasal polyposis may develop under different pathogenetic mechanisms rendering the typical macroscopic classification of CRS, with or without nasal polyps, rather deficient. Currently, we approach nasal polyposis, in terms of diagnosis and treatment, according to its endotype, which means that we focus on the specific cells and cytokines that are participating in its pathogenesis. It appears that the molecular procedures that contribute to polyp formation, initiating with a Th-2 response of the adaptive immune system, are local phenomena occurring in the sub-epithelial layers of the mucosa. Several hypotheses are trying to approach the etiology that drives the immune response towards Th-2 type. Extrinsic factors, like fungi, Staphylococcus superantigens, biofilms, and altered microbiome can contribute to a modified and intense local reaction of the immune system. Some hypotheses based on intrinsic factors like the elimination of Treg lymphocytes, low local vitamin-D levels, high levels of leukotrienes, epithelial to mesenchymal transition (EMT) induced by hypoxia, and altered levels of NO, add pieces to the puzzle of the pathogenesis of nasal polyposis. Currently, the most complete theory is that of epithelial immune barrier dysfunction. Intrinsic and extrinsic conditions can damage the epithelial barrier rendering sub-epithelial layers more vulnerable to invasion by pathogens that trigger a Th-2 response of the adaptive immune system. Th2 cytokines, subsequently, induce the accumulation of eosinophils and IgE together with the remodeling of the stroma in the sub-epithelial layers leading, eventually, to the formation of nasal polyps.

Response to intranasal Lactococcus lactis W136 probiotic supplementation in refractory CRS is associated with modulation of non-type 2 inflammation and epithelial regeneration

Justification

We have previously documented that in individuals with chronic rhinosinusitis (CRS) refractory to surgery, intranasal application of live Lactococcus lactis W136, a probiotic bacterium, improves sinus-specific symptoms, SNOT-22, and mucosal aspect on endoscopy, accompanied by a reduction in sinus pathogens and an increase in protective bacteria. The present work explores the molecular mechanisms underpinning these observations using transcriptomics of the sinus mucosa.

Method

Epithelial brushings collected prospectively as a sub-study of the L. lactis W136 clinical trial were used to probe epithelial responses to microbiome supplementation using a hypothesis-free bioinformatic analysis of gene expression analysis. Samples from twenty-four patients with CRS refractory to medical and surgical management were prospectively collected during a clinical trial assessing the effect of 14 days of BID nasal irrigation with 1.2 billion CFU of live L. lactis W136 probiotic bacteria (CRSwNP = 17, CRSsNP = 7). Endoscopically guided sinus brushings were collected as part of the initial study, with brushings performed immediately before and after treatment. Following RNA extraction, samples were assessed using the Illumina HumanHT-12 V4 BeadChip. Differential gene expression was calculated, and pathway enrichment analysis was performed to identify potentially implicated processes.

Results

Differentially identified transcripts and pathways were assessed for the overall population and the clinical phenotypes of CRSwNP and CRSsNP. Patterns of response to treatment were similar across all groups, implicating pathways for the regulation of immunity and epithelial cell regulation. These resemble the patterns of improvement observed following successful treatment with endoscopic sinus surgery or azithromycin.

Conclusion

Gene expression profiling following the application of live bacteria to the diseased sinus epithelium highlights the implication of multiple components of the inflammation-microbiome-epithelial barrier axis implicated in CRS. These effects appear to involve both epithelial restoration and modulation of innate and adaptive immunity, supporting the potential interest of targeting the sinus epithelium and the microbiome as potential CRS therapies.

Probiotics for Otolaryngologic Disorders

Chronic low-level inflammation is a causative factor in many of our common diseases. Switching to an anti-inflammatory diet is an important step that patients can take in for rectifying this risk factor. In this review, the author discusses the essential components of an anti-inflammatory diet and its contribution not only to the overall well-being but also to the body's defense against disease. The human microbiome is reviewed in detail and dietary connections and recommendations are explained for several otolaryngologic conditions.

Unravelling the role of the microbiome in chronic rhinosinusitis

Chronic rhinosinusitis (CRS) is a complex, heterogenous condition with likely infectious and inflammatory causative factors. Renewed interest in the role that microbes play in this condition has stemmed from advancements in microbe identification and parallel research that has implicated the role of the microbiome in other chronic inflammatory conditions. This clinical commentary provides a review of the current literature relevant to chronic rhinosinusitis. Particular focus is paid to factors specific to the investigation of the sinonasal microbiome, evidence for the role of dysbiosis in the disease state and influences that may impact the microbiome. Possible mechanisms of disease and therapeutic implications through microbial manipulation are also reviewed, as are deficiencies and limitations of the current body of research.

Nasal administration of a probiotic assemblage in allergic rhinitis: a placebo-controlled crossover experimental study

BACKGROUND

Topical probiotics have been suggested as a treatment option for allergic rhinitis, as they may skew the immune response towards a beneficial type-1 non-allergic profile. So far observations in man have exclusively involved oral intake. The aim of this study was to examine if a topical/nasal administration of a probiotic assemblage (PA) affects quality of life, symptoms, and signs of allergic rhinitis in a nasal allergen challenge (NAC) model.

METHODS

In a placebo-controlled and crossover design, 24 patients with seasonal allergic rhinitis were subjected to topical/nasal administration with a PA of Lactobacillus rhamnosus SP1, Lactobacillus paracasei 101/37, and Lactococcus lactis L1A for three weeks. The last week of each treatment period was combined with a NAC-series. Efficacy variables were "Mini-Rhinoconjunctivitis Quality of Life Questionnaire" (Mini-RQLQ), "Total Nasal Symptom Score" (TNSS), "Peak Nasal Inspiratory Flow" (PNIF), and "Fractional Exhaled Nitric Oxide" (FeNO). In addition, to assess whether or not the PA produced any pro-inflammatory effect per se, soluble analytes were monitored in nasal lavage fluids. Finally, bacterial cultures, sampled using swabs from the middle nasal meatus, were assessed for presence of the PA by MALDI-TOF analysis.

RESULTS

Administration of the PA did not produce any nasal symptoms (cf. placebo). An innate response was discerned within the PA-run (cf. baseline), but no change in nasal lavage fluid levels of cytokines/mediators were observed cf. placebo except for IL-17/IL-17A (a minor increase in the PA run). Administration of the PA did neither affect Mini-RQLQ, TNSS, PNIF, nor FeNO. No evidence of persistent colonization was observed.

CONCLUSION

Topical/nasal administration of a PA comprising Lactobacillus rhamnosus SP1, Lactobacillus paracasei 101/37, Lactococcus lactis L1A, while likely evoking a minor innate immune response yet being safe, does not affect quality of life, symptoms, or signs of allergic rhinitis.

The Role of Probiotics in Chronic Rhinosinusitis Treatment: An Update of the Current Literature

Chronic rhinosinusitis (CRS) is a significant health problem. It affects 5–12% of the general population. The causes that underlie the onset of CRS are not yet well known. However, many factors may contribute to its onset, such as environmental factors and the host’s general condition. Medical treatment mainly uses local corticosteroids, nasal irrigation, and antibiotics. In recent years, a new therapeutic approach that employs the use of probiotics emerged. Probiotics have been extensively studied as a therapy for dysbiosis and inflammatory pathologies of various parts of the body. We aimed to examine the studies in vivo and in vitro and clinicals reports in the existing literature to update probiotics’ role in rhinosinusitis chronic medical treatment.

In vitro and in vivo evaluation of probiotic properties of Corynebacterium accolens isolated from the human nasal cavity

Corynebacterium accolens strains are increasingly recognized as beneficial bacteria that can confer a health benefit on the host. In the current study, the probiotic potential of three C. accolens strains, C779, C781 and C787 derived from a healthy human nasal cavity were investigated. These strains were examined for their adhesion to HNECs, competition with Staphylococcus aureus for adhesion, toxicity, induction of IL-6, antibiotic susceptibility and the presence of antibiotic resistance and virulence genes. Furthermore, the safety and efficacy of strains were evaluated in vivo using Caenorhabditis elegans. The adhesion capacity of C. accolens to HNECs was strain-dependent. Highest adhesion was observed for strain C781. None of the C. accolens strains tested caused cell lysis. All strains were able to outcompete S. aureus for cell adhesion and caused a significant decrease of IL-6 production by HNECs co-exposed to S. aureus when compared to the control groups. All strains were sensitive or showed intermediate sensitivity to 10 different antibiotics. Whole Genome Sequence analysis showed C. accolens C781 and C787 did not possess antibiotic resistance genes whereas strain C779 harboured 5 genes associated with resistance to Aminoglycoside, Chloramphenicol and Erythromycin. In addition, no virulence genes were detected in any of the 3 strains. Moreover, the tested strains had no detrimental effect on worm survival and induced protection from S. aureus-mediated infection. Taken all together, C. accolens strains, C781 and C787 displayed probiotic potential and hold promise for use in clinical applications for combating dysbiosis in chronic rhinosinusitis.

Effects of nasopharyngeal microbiota in respiratory infections and allergies

The human microbiome, which consists of a collective cluster of commensal, symbiotic, and pathogenic microorganisms living in the human body, plays a key role in host health and immunity. The human nasal cavity harbors commensal bacteria that suppress the colonization of opportunistic pathogens. However, dysbiosis of the nasal microbial community is associated with many diseases, such as acute respiratory infections including otitis media, sinusitis and bronchitis and allergic respiratory diseases including asthma. The nasopharyngeal acquisition of pneumococcus, which exists as a pathobiont in the nasal cavity, is the initial step in virtually all pneumococcal diseases. Although the factors influencing nasal colonization and elimination are not fully understood, the adhesion of opportunistic pathogens to nasopharyngeal mucosa receptors and the eliciting of immune responses in the host are implicated in addition to bacterial microbiota properties and colonization resistance dynamics. Probiotics or synbiotic interventions may show promising and effective roles in the adjunctive treatment of dysbiosis; however, more studies are needed to characterize how these interventions can be applied in clinical practice in the future.

Review: The Nose as a Route for Therapy. Part 2 Immunotherapy

The nose provides a route of access to the body for inhalants and fluids. Unsurprisingly it has a strong immune defense system, with involvement of innate (e.g., epithelial barrier, muco- ciliary clearance, nasal secretions with interferons, lysozyme, nitric oxide) and acquired (e.g., secreted immunoglobulins, lymphocytes) arms. The lattice network of dendritic cells surrounding the nostrils allows rapid uptake and sampling of molecules able to negotiate the epithelial barrier. Despite this many respiratory infections, including SARS-CoV2, are initiated through nasal mucosal contact, and the nasal mucosa is a significant "reservoir" for microbes including Streptococcus pneumoniae, Neisseria meningitidis and SARS -CoV-2. This review includes consideration of the augmentation of immune defense by the nasal application of interferons, then the reduction of unnecessary inflammation and infection by alteration of the nasal microbiome. The nasal mucosa and associated lymphoid tissue (nasopharynx-associated lymphoid tissue, NALT) provides an important site for vaccine delivery, with cold-adapted live influenza strains (LAIV), which replicate intranasally, resulting in an immune response without significant clinical symptoms, being the most successful thus far. Finally, the clever intranasal application of antibodies bispecific for allergens and Intercellular Adhesion Molecule 1 (ICAM-1) as a topical treatment for allergic and RV-induced rhinitis is explained.

Manipulating the infant respiratory microbiomes to improve clinical outcomes: A review of the literature

BACKGROUND

The association between infant respiratory microbiota and disease (including respiratory tract infections and asthma) is increasingly recognised, although the mechanism remains unclear. Respiratory infections and asthma account for a large proportion of infant morbidity and mortality, so the possibility of preventing disease or modifying clinical outcomes by manipulating microbiome development warrants investigation.

OBJECTIVES AND METHODS

We identified studies that investigated the efficacy of live bacteria (probiotics or human challenge) or their substrates to modify respiratory colonisation or clinical outcomes in infants.

ELIGIBILITY CRITERIA

Interventional studies involving infants under one year of age, administration of live bacteria or their substrates, and outcome measures including bacterial colonisation, microbiome profile, or respiratory disease phenotypes.

RESULTS AND LIMITATIONS

Some bacterial interventions can reduce infant respiratory infections, although none have been shown to reduce asthma incidence. The literature is heterogeneous in design and quality, precluding meaningful meta-analysis.

CONCLUSIONS

Upper respiratory tract infant microbiome manipulation may alter outcomes in respiratory tract infection, but further well-conducted research is needed to confirm this. Improved regulation of proprietary bacterial products is essential for further progress.

Lactobacilli Have a Niche in the Human Nose

Although an increasing number of beneficial microbiome members are characterized for the human gut and vagina, beneficial microbes are underexplored for the human upper respiratory tract (URT). In this study, we demonstrate that taxa from the beneficial Lactobacillus genus complex are more prevalent in the healthy URT than in patients with chronic rhinosinusitis (CRS). Several URT-specific isolates are cultured, characterized, and further explored for their genetic and functional properties related to adaptation to the URT. Catalase genes are found in the identified lactobacilli, which is a unique feature within this mostly facultative anaerobic genus. Moreover, one of our isolated strains, Lactobacillus casei AMBR2, contains fimbriae that enable strong adherence to URT epithelium, inhibit the growth and virulence of several URT pathogens, and successfully colonize nasal epithelium of healthy volunteers. This study thus demonstrates that specific lactobacilli are adapted to the URT and could have a beneficial keystone function in this habitat.

Lactic acid bacteria as probiotics for the nose?

Several studies have recently pointed towards an increased occurrence and prevalence of several taxa of the lactic acid bacteria (LAB) in the microbiota of the upper respiratory tract (URT) under healthy conditions versus disease. These include several species of the Lactobacillales such as Lacticaseibacillus casei, Lactococcus lactis and Dolosigranulum pigrum. In addition to physiological studies on their potential beneficial functions and their long history of safe use as probiotics in other human body sites, LAB are thus increasingly to be explored as alternative or complementary treatment for URT diseases. This review highlights the importance of lactic acid bacteria in the respiratory tract and their potential as topical probiotics for this body site. We focus on the potential probiotic properties and adaptation factors that are needed for a bacterial strain to optimally exert its beneficial activity in the respiratory tract. Furthermore, we discuss a range of in silico, in vitro and in vivo models needed to obtain better insights into the efficacy and adaptation factors specifically for URT probiotics. Such knowledge will facilitate optimal strain selection in order to conduct rigorous clinical studies with the most suitable probiotic strains. Despite convincing evidence from microbiome association and in vitro studies, the clinical evidence for oral or topical probiotics for common URT diseases such as chronic rhinosinusitis (CRS) needs further substantiation.

International consensus statement on allergy and rhinology: rhinosinusitis 2021

I.

EXECUTIVE SUMMARY

BACKGROUND: The 5 years since the publication of the first International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICAR-RS) has witnessed foundational progress in our understanding and treatment of rhinologic disease. These advances are reflected within the more than 40 new topics covered within the ICAR-RS-2021 as well as updates to the original 140 topics. This executive summary consolidates the evidence-based findings of the document.

METHODS

ICAR-RS presents over 180 topics in the forms of evidence-based reviews with recommendations (EBRRs), evidence-based reviews, and literature reviews. The highest grade structured recommendations of the EBRR sections are summarized in this executive summary.

RESULTS

ICAR-RS-2021 covers 22 topics regarding the medical management of RS, which are grade A/B and are presented in the executive summary. Additionally, 4 topics regarding the surgical management of RS are grade A/B and are presented in the executive summary. Finally, a comprehensive evidence-based management algorithm is provided.

CONCLUSION

This ICAR-RS-2021 executive summary provides a compilation of the evidence-based recommendations for medical and surgical treatment of the most common forms of RS.

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.

Probiotic nasal spray development by spray drying

The upper respiratory tract (URT) is the main entrance point for many viral and bacterial pathogens, and URT infections are among the most common infections in the world. Recent evidences by our own group and others imply the importance of lactobacilli as gatekeepers of a healthy URT. However, the benefits of putting health-promoting microbes or potential probiotics, such as these URT lactobacilli, in function of URT disease control and prevention is underestimated, among others because of the absence of adequate formulation modalities. Therefore, this study entails important aspects in probiotic nasal spray development with a novel URT-derived probiotic strain by spray drying. We report quantitative and qualitative analysis of several spray-dried formulations, i.e. powders for reconstitution, based on disaccharide or sugar alcohol combinations with a polymer, including their long-term stability. Four formulations with the highest survival of >10⁹ (Colony Forming Units) CFU/g after 28 weeks were further examined upon reconstitution which confirmed sufficiency of one bottle/dosage form during 7 days and rheological properties of shear-thinning. Tests also demonstrated maintained viability and cell morphology overall upon spraying through a nasal spray bottle in all 4 formulations. Lastly, application suitability in terms of high adherence to Calu-3 cells and antimicrobial activity against common URT pathogens was demonstrated and was not impacted neither by powder production process nor by spraying of reconstituted powder through a nasal spray device.

Lacticaseibacillus casei AMBR2 modulates the epithelial barrier function and immune response in a donor-derived nasal microbiota manner

Live biotherapeutic products (LBP) are emerging as alternative treatment strategies for chronic rhinosinusitis. The selection of interesting candidate LBPs often involves model systems that do not include the polymicrobial background (i.e. the host microbiota) in which they will be introduced. Here, we performed a screening in a simplified model system of upper respiratory epithelium to assess the effect of nasal microbiota composition on the ability to attach and grow of a potential LBP, Lacticaseibacillus casei AMBR2, in this polymicrobial background. After selecting the most permissive and least permissive donor, L. casei AMBR2 colonisation in their respective polymicrobial backgrounds was assessed in more physiologically relevant model systems. We examined cytotoxicity, epithelial barrier function, and cytokine secretion, as well as bacterial cell density and phenotypic diversity in differentiated airway epithelium based models, with or without macrophage-like cells. L. casei AMBR2 could colonize in the presence of both selected donor microbiota and increased epithelial barrier resistance in presence of donor-derived nasal bacteria, as well as anti-inflammatory cytokine secretion in the presence of macrophage-like cells. This study highlights the potential of L. casei AMBR2 as LBP and the necessity to employ physiologically relevant model systems to investigate host–microbe interaction in LBP research.

Effect of Probiotics on Allergic Rhinitis: A Randomized, Controlled, Clinical Trial

Background:

Allergic rhinitis (AR) is one of the most common diseases in the world and affects about 10-50% of the general population. Probiotics are live microorganisms that help the normal state of the intestine, and if prescribed correctly, they can stimulate the mucosal immune system to prevent inflammatory symptoms of allergy and atopy. The present study aims to investigate the role of probiotics in the treatment of AR when added to standard therapy as adjuvant agents.

Materials and Methods:

In this clinical trial study, 28 patients older than 15 years with AR randomly divided into probiotics and control groups. The probiotics group received standard therapy for AR accompanied by probiotic capsules every 12 hours for eight weeks, whereas the control group received standard therapy for AR with placebo capsules as the same protocol. Data were analyzed using SPSS Version 23 (IBM Corporation, Armonk, NY, USA) and, the P-value less than 0.05 was considered statistically significant.

Results:

In the probiotics group, 14.3% of patients had sneezing at the baseline, which significantly decreased to 4.6% (P<0.01). Also, the necessity for nasal and oral corticosteroids after treatment with probiotics in the probiotics group was less than the control group (P<0.01). Although cough, nasal discharge, conchae hypertrophy, and night sleep disorders reduced after treatment with probiotics, this reduction was not statistically significant between the two groups.

Conclusion:

Based on the results of this clinical trial, the use of probiotics had no significant effect on the outcome of patients with AR.

Immunoactive preparations and regulatory responses in the respiratory tract: potential for clinical application in chronic inflammatory airway diseases

Introduction: The prevalence of chronic inflammatory airway diseases is rising. Their treatment with corticosteroids increases infection risk, while overuse of antimicrobial agents may increase morbidity and antimicrobial resistance. Nonspecific immunomodulatory compounds alter immune responses to both infectious and atopic challenges. These compounds may offer an alternative approach for symptom reduction and prophylaxis against both infections and exacerbations in chronic inflammatory airway disease.Areas covered: We assessed the available data on the efficacy of nonspecific immunomodulators including bacterial lysates, synthetic compounds, and vaccines in chronic rhinosinusitis (CRS); allergic and non-allergic rhinitis; chronic obstructive pulmonary disease (COPD), and asthma. A search of PubMed was carried out using the 'Clinical Trials' filter for each condition and immunomodulatory product detailed below, where available, data from meta-analyses were reported.Expert opinion: Pre-clinical data has revealed a coherent mechanistic path of action for oral immunomodulators on the respiratory immune system, principally via the gut-lung immune axis. In patients with asthma, allergic rhinitis, CRS, and COPD immunomodulatory therapy reduces symptoms, exacerbations, hospitalizations, and drug consumption. However, data are heterogeneous, and study quality remains limited. A lack of high-quality recent trials remains the major unmet research need in the field.

The Microbiome of the Nose-Friend or Foe?

Recently, multiple studies regarding the human microbiota and its role on the development of disease have emerged. Current research suggests that the nasal cavity is a major reservoir for opportunistic pathogens, which can then spread to other sections of the respiratory tract and be involved in the development of conditions such as allergic rhinitis, chronic rhinosinusitis, asthma, pneumonia, and otitis media. However, our knowledge of how nasal microbiota changes originate nasopharyngeal and respiratory conditions is still incipient. Herein, we describe how the nasal microbiome in healthy individuals varies with age and explore the effect of nasal microbiota changes in a range of infectious and immunological conditions. We also describe the potential health benefits of human microbiota modulation through probiotic use, both in disease prevention and as adjuvant therapy. Current research suggests that patients with different chronic rhinosinusitis phenotypes possess distinct nasal microbiota profiles, which influence immune response and may be used in the future as biomarkers of disease progression. Probiotic intervention may also have a promising role in the prevention and adjunctive treatment of acute respiratory tract infections and allergic rhinitis, respectively. However, further studies are needed to define the role of probiotics in the chronic rhinosinusitis.

Dual and Triple Epithelial Coculture Model Systems with Donor-Derived Microbiota and THP-1 Macrophages To Mimic Host-Microbe Interactions in the Human Sinonasal Cavities

Despite the relevance of the resident microbiota in sinonasal health and disease and the need for cross talk between immune and epithelial cells in the upper respiratory tract, these parameters have not been combined in a single in vitro model system. We have developed a coculture system of differentiated respiratory epithelium and natural nasal microbiota and incorporated an immune component. As indicated by absence of cytotoxicity and stable cytokine profiles and epithelial integrity, nasal microbiota from human origin appeared to be well tolerated by host cells, while microbial community composition remained representative for that of the human (sino)nasal cavity. Importantly, the introduction of macrophage-like cells enabled us to obtain a differential readout from the epithelial cells dependent on the donor microbial background to which the cells were exposed. We conclude that both model systems offer the means to investigate host-microbe interactions in the upper respiratory tract in a more representative way.

The epithelium of the human sinonasal cavities is colonized by a diverse microbial community, modulating epithelial development and immune priming and playing a role in respiratory disease. Here, we present a novel in vitro approach enabling a 3-day coculture of differentiated Calu-3 respiratory epithelial cells with a donor-derived bacterial community, a commensal species (Lactobacillus sakei), or a pathobiont (Staphylococcus aureus). We also assessed how the incorporation of macrophage-like cells could have a steering effect on both epithelial cells and the microbial community. Inoculation of donor-derived microbiota in our experimental setup did not pose cytotoxic stress on the epithelial cell layers, as demonstrated by unaltered cytokine and lactate dehydrogenase release compared to a sterile control. Epithelial integrity of the differentiated Calu-3 cells was maintained as well, with no differences in transepithelial electrical resistance observed between coculture with donor-derived microbiota and a sterile control. Transition of nasal microbiota from in vivo to in vitro conditions maintained phylogenetic richness, and yet a decrease in phylogenetic and phenotypic diversity was noted. Additional inclusion and coculture of THP-1-derived macrophages did not alter phylogenetic diversity, and yet donor-independent shifts toward higher Moraxella and Mycoplasma abundance were observed, while phenotypic diversity was also increased. Our results demonstrate that coculture of differentiated airway epithelial cells with a healthy donor-derived nasal community is a viable strategy to mimic host-microbe interactions in the human upper respiratory tract. Importantly, including an immune component allowed us to study host-microbe interactions in the upper respiratory tract more in depth.

IMPORTANCE Despite the relevance of the resident microbiota in sinonasal health and disease and the need for cross talk between immune and epithelial cells in the upper respiratory tract, these parameters have not been combined in a single in vitro model system. We have developed a coculture system of differentiated respiratory epithelium and natural nasal microbiota and incorporated an immune component. As indicated by absence of cytotoxicity and stable cytokine profiles and epithelial integrity, nasal microbiota from human origin appeared to be well tolerated by host cells, while microbial community composition remained representative for that of the human (sino)nasal cavity. Importantly, the introduction of macrophage-like cells enabled us to obtain a differential readout from the epithelial cells dependent on the donor microbial background to which the cells were exposed. We conclude that both model systems offer the means to investigate host-microbe interactions in the upper respiratory tract in a more representative way.

Future topical medications in chronic rhinosinusitis

BACKGROUND

Research has progressed rapidly in recent decades to better understand the etiopathogenesis and management paradigms of chronic rhinosinusitis (CRS). Although oral antibiotics often mitigate symptoms in acute CRS exacerbations, eradication of polymicrobial biofilms and multidrug-resistant bacteria remains a challenge. The goal of this review is to summarize and discuss the potential and pitfalls of topical medications in the treatment of CRS.

METHODS

A related literature review was performed using PubMed and Scopus, with only the English database included.

RESULTS

The main therapies were selected and separated in sections. Details regarding future topical treatments of CRS were summarized and discussed.

CONCLUSION

The ease of access of the sinonasal mucosa positions CRS as a disease with high potential for local topical treatment. The ultimate adoption of topical agents will require continued expansion of our understanding of novel local targets in CRS as well as improved methods to deliver and retain the drug of interest at the site of activity.

Evaluation of the efficacy of Lactobacillus plantarum HEAL9 and Lactobacillus paracasei 8700:2 on aspects of common cold infections in children attending day care: a randomised, double-blind, placebo-controlled clinical study

BACKGROUND

The combination of Lactobacillus plantarum HEAL9 and Lactobacillus paracasei 8700:2 (commercially available as Probi Defendum^®) has previously been reported to reduce the incidence, duration and severity of naturally acquired common colds in adults. The aim of the present study was to evaluate the impact of Probi Defendum^® on aspects of common cold in healthy children 1-6 years of age attending day care.

METHODS

A total of 131 children, out of the planned 320, were recruited into the study during 1 common cold season and randomised to consume once daily either 10⁹ CFU (colony forming units) of the probiotic product or placebo. Due to unforeseen reasons, the recruitment of more children did not continue beyond the first cold season.

RESULTS

There were 106 children that completed the study out of the 131 randomised. Daily consumption of the probiotic product for a period of 3 months significantly reduced the severity of the symptom "nasal congestion/runny nose" with a mean severity score for the whole study period of 7.5 ± 9.7 in the probiotic group and 13.9 ± 15.2 in the placebo (p < 0.05). Moreover, significantly less concomitant medication was used in the probiotic group. When the data were projected to a larger population corresponding to the originally estimated sample size, the results were in favour of the probiotic group regarding the reduced absence from day care (p < 0.05), reduced mean total severity per day in the reported episodes (p < 0.05) and reduced severity of the symptom "crying more than usual" (p < 0.05).

CONCLUSION

Intake of Probi Defendum^® once daily for a period of 3 months was beneficial to children and reduced the severity of common colds.

The microbiome of the upper respiratory tract in health and disease

The human upper respiratory tract (URT) offers a variety of niches for microbial colonization. Local microbial communities are shaped by the different characteristics of the specific location within the URT, but also by the interaction with both external and intrinsic factors, such as ageing, diseases, immune responses, olfactory function, and lifestyle habits such as smoking. We summarize here the current knowledge about the URT microbiome in health and disease, discuss methodological issues, and consider the potential of the nasal microbiome to be used for medical diagnostics and as a target for therapy.

Probiotics for the airways: Potential to improve epithelial and immune homeostasis

Probiotics are live microorganisms that, when administered in adequate amounts, confer health benefit on the host. The therapeutic effects of probiotics have been mostly studied in the gastrointestinal tract, but recent evidence points toward the potential of these bacteria to prevent and/or treat chronic airway diseases. In this review, possible mechanisms of action of probiotics in the airways are described, with a particular focus on their capacity to modulate the epithelial barrier function and their mode of interaction with the immune system. Indeed, probiotic bacteria, mostly lactobacilli, can promote the expression and regulation of tight junctions and adherence junctions, resulting in the restoration of a defective epithelial barrier. These bacteria interact with the epithelial barrier and immune cells through pattern recognition receptors, such as Toll-like receptors, which upon activation can stimulate or suppress various immune responses. Finally, the clinical potential of probiotics to treat inflammatory diseases of the upper and lower respiratory tract, and the difference between their mode of application (eg, oral or nasal) are discussed here.

The Potential for Topical Probiotic Treatment of Chronic Rhinosinusitis, a Personal Perspective

This review describes the rationale for topical probiotic intervention, the obstacles we are facing and a strategy for future research in the use of probiotics to modify CRS symptoms and disease expression. Recent advances in molecular microbiology has revealed a plethora of microbial DNA in the nasal cavity and sinuses of healthy subjects as well as in chronic sinusitis (CRS) patients. An infection is today rather seen as an imbalance between the commensal microbiome and the bacterial pathogens, resulting in a reduction in commensal bacterial diversity, combined with an increase in the growth of microbes eliciting an inflammatory response. This will in turn lead to the clinical symptoms of sinusitis. Probiotics (microorganisms that confer a health benefit) can be used either as a form of living antibiotics treatment, or as an immune-modulatory intervention. Topical probiotics, which is the focus of this review, have shown efficacy in a limited number of trials in otitis media and tonsillitis, but to date not in CRS. Although bacterial interference capacity against pathogens can be determined in in vitro experiments, it may not translate to a health benefit. This limits the role of laboratory research in identifying probiotic strains with a clinical benefit. To gain more clinical experience without further delay, I recommend future research to focus on empirical clinical trials in well-defined CRS patient populations and study the underlying mechanisms in more detail once a clinical benefit has been established.