Therapeutic Effects Of Probiotics Research Articles

Computational prediction of new therapeutic effects of probiotics

Probiotics are living microorganisms that provide health benefits to their hosts, potentially aiding in the treatment or prevention of various diseases, including diarrhea, irritable bowel syndrome, ulcerative colitis, and Crohn’s disease. Motivated by successful applications of link prediction in medical and biological networks, we applied link prediction to the probiotic-disease network to identify unreported relations. Using data from the Probio database and International Classification of Diseases-10th Revision (ICD-10) resources, we constructed a bipartite graph focused on the relationship between probiotics and diseases. We applied customized link prediction algorithms for this bipartite network, including common neighbors, Jaccard coefficient, and Adamic/Adar ranking formulas. We evaluated the results using Area under the Curve (AUC) and precision metrics. Our analysis revealed that common neighbors outperformed the other methods, with an AUC of 0.96 and precision of 0.6, indicating that basic formulas can predict at least six out of ten probable relations correctly. To support our findings, we conducted an exact search of the top 20 predictions and found six confirming papers on Google Scholar and Science Direct. Evidence suggests that Lactobacillus jensenii may provide prophylactic and therapeutic benefits for gastrointestinal diseases and that Lactobacillus acidophilus may have potential activity against urologic and female genital illnesses. Further investigation of other predictions through additional preclinical and clinical studies is recommended. Future research may focus on deploying more powerful link prediction algorithms to achieve better and more accurate results.

Therapeutic Effects of Probiotics In The Reduction of Neonatal Hyperbilirubinemia

Objective: To evaluate probiotics' effects in reducing hyperbilirubinemia in late preterm and term neonates. Study Design: Quasi-experimental study Place and Duration of Study: Department of Neonatology, Pakistan Institute of Medical Sciences (PIMS), Islamabad Pakistan, from Oct 2018 to Mar 2019. Methodology: The quasi-experimental study was conducted on 60 neonates with hyperbilirubinemia. They were randomlydivided into two Groups. Group-A (n=30) received phototherapy. Group-B (n=30) received probiotics containing Lactobacillus reuteri at a dose of 5 drops daily for three days, in addition to phototherapy. Total serum bilirubin was calculated at 0, 24 and 72 hours for both Groups. Results: In Group-A, the mean total bilirubin in mg/dl at 0, 24 and 72 hours were 18.14±2.35, 15.28±2.93 and 12.31±2.29, respectively. Similarly, in Group-B, it was 19.86±5.85, 16.23±4.01 and 10.75±2.23 at 0, 24 and 72 hours, respectively. There was an insignificant statistical difference in mean total bilirubin between Groups A and B at 0 and 24 hours (p<0.001). However, when comparison was made at 72 hours, a significant statistical difference was observed in Group-B (Intervention Group) (p=0.005) Conclusion: Probiotics significantly lowered total serum bilirubin in neonates with hyperbilirubinemia. Further studies are required to evaluate its role in physiological and pathological jaundice.

Antibacterial, probiotic and immunomodulatory properties of L. acidophilus La‑14

Many scientific studies show the preventive and therapeutic effects of probiotics in various diseases. The L. acidophilus La‑14 strain has proven antibacterial, probiotic and immunomodulatory effectiveness, has a long history of use and does not cause the development of antibiotic resistance. Further research is needed to determine the optimal dose and duration of probiotic intake.

Probiotics for the treatment of ulcerative colitis: a review of experimental research from 2018 to 2022.

Ulcerative colitis (UC) has become a worldwide public health problem, and the prevalence of the disease among children has been increasing. The pathogenesis of UC has not been elucidated, but dysbiosis of the gut microbiota is considered the main cause of chronic intestinal inflammation. This review focuses on the therapeutic effects of probiotics on UC and the potential mechanisms involved. In animal studies, probiotics have been shown to alleviate symptoms of UC, including weight loss, diarrhea, blood in the stool, and a shortened colon length, while also restoring intestinal microecological homeostasis, improving gut barrier function, modulating the intestinal immune response, and attenuating intestinal inflammation, thereby providing theoretical support for the development of probiotic-based microbial products as an adjunctive therapy for UC. However, the efficacy of probiotics is influenced by factors such as the bacterial strain, dose, and form. Hence, the mechanisms of action need to be investigated further. Relevant clinical trials are currently lacking, so the extension of animal experimental findings to clinical application requires a longer period of consideration for validation.

Prophylactic vs. Therapeutic Effect of Probiotics on the Inflammation Mediated by the NF-κB Pathway in Inflammatory Bowel Conditions.

Probiotic supplements consumed adequately at the proper time can affect health by modulating inflammatory pathways in gastrointestinal epithelial cells and modifying the resultant inflammatory response. The current study applied in vitro models to investigate the effectiveness of probiotics in modulating inflammatory pathways and altering inflammatory gene expression in gastrointestinal epithelial cells, with the ultimate goal of promoting probiotic consumption as a therapeutic and preventive measure for chronic inflammatory bowel conditions. HT-29 cells were treated with Gram-negative bacteria to evaluate the changes in pathways related to inflammation activities before and after treatment with a Lactobacillus spp. cocktail (L. plantarum, L. rhamnosus, L. brevis, and L. ruteri) and a Bifidobacterium spp. cocktail (B. bifidum, B. langum, and B. breve) using the real-time PCR method and ELISA for IL-1β and IL-6 as pro-inflammatory cytokines. The results showed that the expression of NF-κB signaling pathway genes and IL-1β and IL-6 cytokines increased after exposure to Gram-negative components. In contrast, all probiotic combinations significantly decreased the expression of genes and the secretion of cytokines. However, this decrease was significantly smaller in cells that underwent probiotic treatment after inflammation induction. In addition, cocktails containing combined Lactobacillus and Bifidobacterium demonstrated robust anti-inflammatory activity relative to solo cocktails. Our observations confirm that probiotic consumption could positively impact inflammatory conditions and alleviate inflammatory symptoms; they can be particularly effective as a preventive measure. Our study provides preliminary evidence to support the lifetime consumption of probiotics.

Gut-brain axis: altered microbiome and depression - review.

The concept of a 'gut-brain axis' was recently developed when the complex communications between the brain and the gut became evident. The interaction may affect emotions, motivation, mood, and higher cognitive functions as well as gut homeostasis. Human microbe symbiosis's merits are now acknowledged to transcend human mental health. Research has recently indicated that the gut-brain axis plays a vital role in brain health maintenance. The term 'gut-brain axis' can only partially capture the intricacy of these interactions. Dysbiosis of the gut commensals has been seen in patients with psychiatric diseases, such as depression. Major depressive disorder is caused by complicated interactions between the individual gene and the environment. In a forced swimming test, P. Zheng et al. discovered that germ-free mice with no gut microbiota had a shorter immobility duration than healthy mice. More radical effects were expressed on the use of probiotics rather than prebiotics and postbiotics in reducing the symptoms of depression in patients with major depressive disorder. One of prime importance can be given to exploring more microbiota to investigate the better therapeutic effects of probiotics, prebiotics, and postbiotics.

Therapeutic effect of probiotics on metabolic indices and clinical signs in age-related macular degeneration

ABSTRACT Probiotics positively influence age-related macular degeneration (ARMD) given their propensity to attenuate oxidative and inflammatory stress. We addressed the impact of probiotics on metabolic profiles, clinical indices, inflammatory and oxidative stress parameters in ARMD patients. We performed a randomized, double-blind, placebo-controlled trial analyzing 57 subjects with ARMD aged between 50 and 85 years. Subjects were randomized into two groups, and received daily for 8 weeks either probiotic capsule or placebo. Fasting blood samples were obtained at baseline and after the 8-week intervention for the determination of metabolic profiles and oxidative stress biomarkers. After the 8-week intervention, compared with the placebo, probiotic supplementation significantly increased means HDL-cholesterol (Probiotic group: +3.86±4.42 vs. Placebo group: −0.55±4.93 mg/dL, P = .001), plasma total antioxidant capacity (TAC) (Probiotic group: +77.43±168.30 vs. Placebo group: −23.12±169.22 mmol/L, P = .02) and significantly decreased malondialdehyde (MDA) levels (Probiotic group: −0.18±0.46 vs. Placebo group: +0.18±0.25 µmol/L, P = .001). There was no significant effect of probiotic administration on other metabolic profiles and clinical symptoms. Overall, an eight-week probiotic administration among ARMD patients had beneficial effects on TAC, MDA and HDL-cholesterol levels; however, it did not affect clinical signs and other metabolic profiles.

Probiotics (Lactobacillus plantarum HNU082) Supplementation Relieves Ulcerative Colitis by Affecting Intestinal Barrier Functions, Immunity-Related Gene Expression, Gut Microbiota, and Metabolic Pathways in Mice.

Probiotics can effectively improve ulcerative colitis (UC), but the mechanism is still unclear. Here, shotgun metagenome and transcriptome analyses were performed to explore the therapeutic effect and the mechanism of the probiotic Lactobacillus plantarum HNU082 (Lp082) on UC. The results showed that Lp082 treatment significantly ameliorated dextran sulfate sodium (DSS)-induced UC in mice, which was manifested as increases in body weight, water intake, food intake, and colon length and decreases in disease activity index (DAI), immune organ index, inflammatory factors, and histopathological scores after Lp082 intake. An in-depth study discovered that Lp082 could improve the intestinal mucosal barrier and relieve inflammation by cooptimizing the biological barrier, chemical barrier, mechanical barrier, and immune barrier. Specifically, Lp082 rebuilt the biological barrier by regulating the intestinal microbiome and increasing the production of short-chain fatty acids (SCFAs). Lp082 improved the chemical barrier by reducing intercellular cell adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule (VCAM) and increasing goblet cells and mucin2. Lp082 ameliorated the mechanical barrier by increasing zonula occludens-1 (ZO-1), zonula occludens-2 (ZO-2), and occludin while decreasing claudin-1 and claudin-2. Lp082 optimized the immune barrier by reducing the content of interleukin-1β (IL-1β), IL-6, tumor necrosis factor-α (TNF-α), myeloperoxidase (MPO), and interferon-γ (IFN-γ) and increasing IL-10, transforming growth factor-β1 (TGF-β1), and TGF-β2, inhibiting the NF-κB signaling pathway. Taken together, probiotic Lp082 can play a protective role in a DSS-induced colitis mouse model by protecting the intestinal mucosal barrier, attenuating the inflammatory response, and regulating microbial imbalance. This study provides support for the development of probiotic-based microbial products as an alternative treatment strategy for UC. IMPORTANCE Many studies have focused on the therapeutic effect of probiotics on ulcerative colitis (UC), but few studies have paid attention to the mechanism of probiotics, especially the therapeutic effect. This study suggests that Lp082 has a therapeutic effect on colitis in mice. Its mechanisms of action include protecting the mucosal barrier and actively modulating the gut microbiome, modulating inflammatory pathways, and reducing neutrophil infiltration. Our study enriches the mechanism and provides a new prospect for probiotics in the treatment of colitis, helps to deepen the understanding of the intestinal mucosal barrier, and provides guidance for the future probiotic treatment of human colitis.

Tryptophan metabolites in depression: Modulation by gut microbiota.

Clinical depression is a multifactorial disorder and one of the leading causes of disability worldwide. The alterations in tryptophan metabolism such as changes in the levels of serotonin, kynurenine, and kynurenine acid have been implicated in the etiology of depression for more than 50 years. In recent years, accumulated evidence has revealed that gut microbial communities, besides being essential players in various aspects of host physiology and brain functioning are also implicated in the etiology of depression, particularly through modulation of tryptophan metabolism. Therefore, the aim of this review is to summarize the evidence of the role of gut bacteria in disturbed tryptophan metabolism in depression. We summed up the effects of microbiota on serotonin, kynurenine, and indole pathway of tryptophan conversion relevant for understanding the pathogenesis of depressive behavior. Moreover, we reviewed data regarding the therapeutic effects of probiotics, particularly through the regulation of tryptophan metabolites. Taken together, these findings can open new possibilities for further improvement of treatments for depression based on the microbiota-mediated modulation of the tryptophan pathway.

The preventive and therapeutic effects of probiotics on mastitis: A systematic review and meta-analysis.

Acute mastitis is one of the main reasons why breastfeeding women stop breastfeeding, and medication should be used with caution. Considering the uncertainty of mastitis infection and the indications of antibiotic use, as well as the problem of drug resistance and the safety of medication during lactation, probiotics have become an alternative treatment choice. However, a meta-analysis of the effects of probiotics in preventing and treating lactational mastitis is still lacking. Therefore, we searched six electronic databases and the sites of clinical trial registration, a total of six randomized controlled trials were included in this meta-analysis, which showed that oral probiotics during pregnancy can reduce the incidence of mastitis (RR: 0.49, 95% CI: 0.35 to 0.69; p<0.0001). After oral administration of probiotics, the counts of bacteria in the milk of healthy people and mastitis patients were both significantly reduced (in healthy people: MD: -0.19, 95% CI: -0.23 to -0.16, p<0.00001; in mastitis patients: MD: -0.89, 95% CI: -1.34 to -0.43, p = 0.0001). These indicate that to a certain extent, probiotics are beneficial in reducing the incidence rate of mastitis during lactation and some related mastitis symptoms. However, high-quality multicenter clinical trials are still needed to support this result.

Antimicrobial and therapeutic effect of probiotics in cases of experimental purulent wounds

Probiotics based on bacteria of the genus Bacillus with a multifactorial mechanism of action are considered as a possible alternative to antibiotics in the treatment of purulent wounds. The aim of the study was to determine the antimicrobial and therapeutic effect of the Arederma probiotic preparation containing probiotic strains of the genus Bacillus in an experimental model of a purulent wound in animals. The antimicrobial efficacy of the probiotic against test strains and clinical isolates of pathogenic and opportunistic microorganisms was studied using the method of delayed antagonism. Staphylococcus aureus ATCC 6538 and Streptococcus pyogenes K-7 were used to model a purulent wound. From the surface of the wounds, bacteria of Staphylococcus, Streptococcus, Enterobacteriaceae, Pseudomonas genera and Enterobacteriaceae family were sown on appropriate selective media for the cultivation and enumeration of different groups of microorganisms by generally accepted microbiological research methods. The formation of a purulent wound in rabbits caused by mechanical skin damage and subsequent double infection with Staphylococcus aureus ATCC 6538 and Streptococcus pyogenes K-7 strains was accompanied with a pronounced inflammatory process, necrosis, the formation of purulent exudate and general intoxication. Representatives of the genera Staphylococcus and Streptococcus, microscopic fungi and, to a lesser extent, members of the family Enterobacteriaceae and Pseudomonas were found on the surface of purulent wounds, which confirmed the development of the infectious-inflammatory process. Treatment of purulent wounds with a suspension of probiotic preparation once a day for 4 days led to their faster healing (gradual attenuation of the inflammatory process, reduction of edema and discharge, as well as their disappearance) compared with untreated purulent wounds (control). Representatives of the Staphylococcus and Streptococcus genera, as well as microscopic fungi, presented in purulent wounds treated with probiotic preparation in much smaller numbers than in the control, and bacteria of the Pseudomonas genus and the Enterobacteriaceae family were not detected at all. The effective antimicrobial effect of this probiotic preparation against opportunistic and pathogenic microorganisms was confirmed by in vitro studies. Therefore, the Arederma probiotic preparation showed an effective therapeutic and antimicrobial effect in the experimental model of a purulent wound in animals, so it can be recommended for further preclinical and clinical studies.

Investigation of the effect of Lactobacillus paracasei TD3 on cutaneous wound healing and induction of angiogenesis on male Wistar rats

Skin plays an essential role in the prevention of pathogenic microorganisms entrance. It is also considered as the first line of immune defense in our body. The therapeutic effects of probiotics on wound healing are well reported over the past decade. Nevertheless, there are limited publications about the impact of probiotics on skin wound healing. Here we assessed the effect of Lactobacillus paracasei TD3 on cutaneous wound healing in male Wistar rats. During this research, thirty-six male Wistar rats grouped into control positive, control negative, and trial groups, then the skins of rats were incised to make a full-thickness wound. An ointment produced from probiotic L. paracasei TD3 was administrated to the trial group, and immunohistological factors of each host were evaluated and compared with control groups. The final results showed that although L. paracasei TD3 could proceed the wound closure earlier than other groups and could induce angiogenesis in trial group, it could not cause any significant changes in the levels of monocytes, lymphocyte, mast cells and polymorphonuclear leukocytes in the trial group compared to control groups. This probiotic bacterium may be effective besides other probiotic bacteria.

The place of probiotics in the treatment of non-alcoholic fatty liver disease

Probiotics are defined as living microorganisms that, when administered in adequate amounts, provide benefits to human health. Probiotics are being successfully used to increase the proportion of commensal gut microbes, which have beneficial effects on the intestinal mucosa and human health in general. The range of uses of probiotics is very wide, but the heterogeneity of studies and inaccurate characterization of probiotic products makes it difficult to interpret the results of the studies. The health benefits have mainly been demonstrated for certain probiotic strains of the following genera: Lactobacillus, Bifidobacterium, Saccharomyces, Enterococcus, Streptococcus, Pediococcus, Leuconostoc, Bacillus, Escherichia coli. The probiotic potential of bacteria is directly related to specific strains, and not to a genus or species of a microorganism.&#x0D; New data on the role of the gut microbiome in the development of non‑alcoholic fatty liver disease (NAFLD) and metabolic disorders such as obesity and diabetes mellitus suggest that correcting the gut microbiota may be a new strategy for the treatment of NAFLD and associated metabolic disorders. Currently, there is no standard pharmacological therapy for hepatic steatosis and, moreover, steatohepatitis. Given the increasing NAFLD prevalence, there is an urgent need to address issues of pharmacological treatment options in this patient population. Probiotics may be ideal candidates for the NAFLD treatment due to their properties, but their effectiveness remains controversial. Such processes as modification of the intestinal microbiota, reduction in the production of harmful metabolites, decrease in the intestinal permeability, and the prevention of inflammation and fibrosis in liver tissue are considered to be the potential therapeutic effects of probiotics at NAFLD.&#x0D;

Role of probiotics in prevention and treatment of enteric infections: a comprehensive review.

Microorganisms that inhabits human digestive tract affect global health and enteric disorders. Previous studies have documented the effectiveness and mode of action of probiotics and classified as human-friendly biota and a competitor to enteric pathogens. Statistical studies reported more than 1.5 billion cases of gastrointestinal infections caused by enteric pathogens and their long-term exposure can lead to mental retardation, temporary or permanent physical weakness, and leaving the patient susceptible for opportunistic pathogens, which can cause fatality. We reviewed previous literature providing evidence about therapeutic approaches regarding probiotics to cure enteric infections efficiently by producing inhibitory substances, immune system modulation, improved barrier function. The therapeutic effects of probiotics have shown success against many foodborne pathogens and their therapeutic effectiveness has been exponentially increased using genetically engineered probiotics. The bioengineered probiotic strains are expected to provide a better and alternative approach than traditional antibiotic therapy against enteric pathogens, but the novelty of these strains also raise doubts about the possible untapped side effects, for which there is a need for further studies to eliminate the concerns relating to the use and safety of probiotics. Many such developments and optimization of the classical techniques will revolutionize the treatments for enteric infections.

Modification of gut microbiota as a method of treatment of irritable bowel syndrome (literature review and own data)

Recently, our knowledge of gut microbiota (GM) disorders in various pathologies has significantly increased. In particular, to date, there is sufficient evidence that various disorders of GM may play a pathogenetic role in irritable bowel syndrome (IBS). Therefore, various methods of GM modification are now considered as a new promising strategy for the treatment of patients with IBS. The use of probiotics, prebiotics, synbiotics, antibiotics and fecal microbiota transplantation (FMT) are considered as methods of GM modification. Many clinical trials have been conducted to examine the therapeutic effect of probiotics on general or specific symptoms of IBS, but most of these studies have been very heterogeneous. Although some meta‑analyzes or systematic reviews show that probiotics may be useful in treating the symptoms of IBS, their findings in the studies differ due to insufficient sample size, poor study design, and the use of different probiotic strains. Currently, only one selective intestinal antibiotic with eubiotic properties is known — rifaximin, the effectiveness and safety of which have been proven in large randomized trials. The authors presented their own experience of rifaximin use at IBS that confirmed its efficiency. Own experience of the FMT conduction in patients with IBS is also presented. It has been revealed that even one‑time treatment significantly affected the GM by reducing the frequency and severity of dysbiotic disorders; it was accompanied by significant clinical effects in most patients that lasted up to 3 months of follow‑up.

Beneficial effect of Lactobacillus plantarum IS-10506 supplementation in adults with atopic dermatitis: a randomized controlled trial

Introduction Although the therapeutic effects of probiotics in atopic dermatitis (AD) are known, the limited findings in adults are inconsistent. Lactobacillus plantarum (LP) IS-10506 was found to improve AD symptoms due to its immunomodulatory effects. Objective To assess the Scoring Atopic Dermatitis Index (SCORAD), the serum immunoglobulin E (IgE), interleukin (IL)-4, interferon-gamma (IFN-γ), forkhead box P3 (Foxp3+), and IL-17 levels in adults with mild and moderate AD after LP IS-10506 supplementation. Methods A randomized double-blind placebo-controlled trial comparing the microencapsulated probiotic (2 × 1010 CFU/day) and placebo (skim milk-Avicel) was conducted at an outpatient clinic on 30 adults with mild and moderate AD. The patients were divided into 2 groups with 15 patients each: intervention and control. Result The SCORAD score was significantly lower in the probiotic than the placebo group on the 8th week. The IL-4 and IL-17 levels were significantly lower in the probiotic than the placebo group. The IFN-γ and Foxp3+ levels were significantly higher in the probiotic than the placebo group. However, the IgE levels remained significantly unchanged. Conclusion The administration of LP IS-10506 is effective for alleviating AD symptoms in adults owing to its immunomodulatory effects.

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.

The role of gut microbiome in the pathogenesis of psoriasis and the therapeutic effects of probiotics.

The adult intestine hosts a huge number of diverse bacterial species, collectively referred to as the microbiome, that reside mainly in the lower gut, where they maintain a symbiotic relationship with their host. Recent research points to a central role of the microbiome in many biological processes. These microbial communities are influenced by multiple environmental and dietary factors and can modulate immune responses. In addition to local effects on the gastrointestinal tract, the microbiota is associated with effects on other organs and tissues, such as the skin. Indeed, an altered microbiome has been associated with skin disorders in several instances. Thus, in this review, we describe the recent advances regarding the interplay between gut microbiota and the skin. We explore how this potential link affects skin homeostasis and its influence on modulating the cutaneous immune response, focusing on psoriasis disorder. Finally, we discuss how to take advantage of this interplay to manage this disorder, particularly through probiotics administration. In the gastrointestinal tract, the microbiome has been proven to be important in the maintenance of the balance between effector T cells and regulatory T cells, and the induction of immunoglobulin A. Moreover, gut bacterial dysbiosis is associated with chronic inflammatory disorders of the skin, such as psoriasis. Thus, the microbiome can be considered an effective therapeutical target for treating this disorder. Despite some limitations, interventions with probiotics seem promising for the development of a preventive therapy by restoring altered microbiome functionality or as an adjuvant in specific immunotherapy.

Correction to: Therapeutic effects of probiotics on neurotoxicity induced by clindamycin and propionic acid in juvenile hamsters.

The original version of this article unfortunately contained a mistake. The family name of the fourth author listed in the title was incorrect, and the correct name is Nadine Moubayed, as noted in the addresses. Her name is now corrected in the author group of this article.

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.