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Immune mechanisms of probiotics. DC, dendritic cells; TJ, tight junction; SCFA, short chain fatty acid; IgA, immunoglobulin A; IgE, immunoglobulin E; IL, interleukin; TNF, tumor necrosis factor; IFN, interferon; NF-κB, nuclear factor-κB; ROS, reactive oxygen species. Reproduced from Iacono A, et al. J Nutr Biochem 2011;22:699-711, with permission of Elsevier Inc.10).
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A complex interplay between genetic and environmental factors partially contributes to the development of allergic diseases by affecting development during prenatal and early life. To explain the dramatic increase in the prevalence of allergic diseases, the hygiene hypothesis proposed that early exposure to infection prevented allergic diseases. Th...
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Allergic diseases are on the increase globally. There has been a doubling in the number of scholars suffering from allergy-related disease in the past two decades. This article describes the predisposing factors which contribute to an increased incidence of allergies within the population. These factors include a genetic predisposition, allergen ex...
Citations
... In ammatory cytokines are produced by Th2 subtype effector T lymphocytes (Th2s) once they have been activated, such as interleukin(IL)-4, IL-5, and IL-13, and nally leads to the enhancement of IgE, which induces the aggravation of AD. Compared to healthy people, AD patients have signi cantly lower levels of short-chain fatty acids (SCFAs) such as propionate and butyrate [39,40]. Propionate and butyrate are important short-chain fatty acids that may inhibit in ammation in AD patients who are prone to Th2-induced and Th17-induced in ammation. ...
... Propionate and butyrate are important short-chain fatty acids that may inhibit in ammation in AD patients who are prone to Th2-induced and Th17-induced in ammation. An analysis of fecal samples from AD patients performed in South Korea found that the abundance of Faecalibacteriumprausnitzii was decreased compared with that of the healthy control group, while the production of SCFA was also signi cantly reduced [39][40][41]. Propionate in the intestinal tract is mainly produced by Dialister [42], bers can be decomposed by Prevotella, and propionate and butyrate are produced [39]. ...
... An analysis of fecal samples from AD patients performed in South Korea found that the abundance of Faecalibacteriumprausnitzii was decreased compared with that of the healthy control group, while the production of SCFA was also signi cantly reduced [39][40][41]. Propionate in the intestinal tract is mainly produced by Dialister [42], bers can be decomposed by Prevotella, and propionate and butyrate are produced [39]. Speci cally, both of them inhibit histone deacetylase [43] and induce peripheral CD4 + T cells to differentiate into Treg cells, IL-10 is then produced, inhibiting Th2 and Th17 cell function [44]. ...
Background
Increasing evidence suggests that alterations in gut microbiota are associated with a variety of skin diseases. However, whether this association reflects a causal relationship remains unknown. We aimed to reveal the causal relationship between gut microbiota and skin diseases, including psoriasis, atopic dermatitis, acne, and lichen planus.
Methods
We obtained full genetic association summary data for gut flora, psoriasis, atopic dermatitis, acne, and lichen planus from public databases and used three methods, mainly inverse variance weighting, to analyze the causal relationships between gut flora and these skin diseases using bidirectional Mendelian randomization, as well as sensitivity and stability analysis of the results using multiple methods.
Results
The results showed that there were 5 associated genera in the psoriasis group, 10 associated genera were obtained in the atopic dermatitis group, a total of 8 associated genera in the acne group, and 6 associated genera in the lichen planus group. The results corrected for false discovery rate showed that Eubacteriumfissicatena(p = 7.10E-05, OR = 1.44,95%CI: 1.20–1.72) and Lactococcus(p = 4.90E-04, OR = 1.37,95%CI: 1.15–1.65) and psoriasis, and Coprococcus-3(p = 0.001, OR = 2.39,95%CI: 1.41–4.03) and acne still showed a causal relationship. In contrast, in the reverse Mendelian randomization results, there was no evidence of an association between these skin diseases and intestinal flora.
Conclusion
We demonstrated a causal relationship between gut microbiota and immune skin diseases and provide a new therapeutic perspective for the study of immune diseases: targeted modulation of dysregulation of specific bacterial taxa to prevent and treat psoriasis, atopic dermatitis, acne, and lichen planus.
... Furthermore, the genus Dialister is a propionate producer in the intestinal tract (38), and genus Prevotella can break down fibers and produce propionate and butyrate (39). Several studies have discovered that the content of short-chain fatty acids (SCFAs) such as propionate and butyrate in patients with AD is significantly lower than that in healthy individuals (40,41). As important SCFAs, propionate and butyrate can inhibit the Th2skewed and Th17-skewed inflammation in AD. ...
Background
Growing evidence shows a significant association between intestinal flora and allergic diseases, specifically atopic dermatitis (AD), allergic rhinitis (AR), and allergic asthma (AA). However, the causality has not yet been clarified.Objective
We conducted a bidirectional two-sample Mendelian randomization (TSMR) analysis to study the causal relationships between intestinal flora classification and AD, AR, or AA.Materials and methodsWe obtained summary data of intestinal flora, AD, AR, and AA from a genome-wide association research. The inverse-variance weighted method is the primary method for analyzing causality in the TSMR analysis. Several sensitivity analyses were conducted to examine the stability of TSMR results. Reverse TSMR analysis was also performed to assess whether there was a reverse causality.ResultsA total of 7 bacterial taxa associated with AD, AR, and AA were identified by the current TSMR analysis. Specifically, the genus Dialister(P=0.034)and genus Prevotella(P=0.047)were associated with a higher risk of AD, whereas class Coriobacteriia (P=0.034) and its child taxon, order Coriobacteriales (P=0.034) and family Coriobacteriaceae (P=0.034), all had a protective effect on AR. In addition, the family Victivallaceae (P=0.019) was identified as a risk factor for AR. We also noticed a positive association between the genus Holdemanella (P=0.046) and AA. The reverse TSMR analysis didn’t suggest any evidence of reverse causality from allergic diseases to the intestinal flora.Conclusion
We confirmed the causal relationship between intestinal flora and allergic diseases and provided an innovative perspective for research on allergic diseases: targeted regulation of dysregulation of specific bacterial taxa to prevent and treat AD, AR, and AA.
... The prevalence of asthma has increased in the past decades. A potential mechanism underlying this high prevalence is the microbial hypothesis which argues that less microbial exposure upregulates the cytokine production of T-helper cells type 2 (Th2), leading to an increase in allergic diseases [3]. The main available treatments currently for asthma include accurate assessment of asthma severity and the use of β2-adrenergic agonists, which are bronchodilators for acute reactions, and anti-inflammatory drugs such as inhaled corticosteroids [4]. ...
Background
Asthma is considered to be a chronic inflammatory disorder of the airways. Probiotics are living microorganisms that are found in the human gut and have protective effects against a wide range of diseases such as allergies. The aim of this study was to investigate the improvement of clinical asthma symptoms and changes in the expression pattern of selective microRNAs in patients with asthma and the changes in IL-4 and IFN-γ plasma levels after receiving probiotics.
Materials and methods
The present study was a randomized, double-blind, placebo-controlled trial that enrolled 40 asthmatic patients. They were treated with probiotics or placebo: 1 capsule/day for 8 weeks. Pulmonary function tests, IL-4 and IFN-γ levels, and expression of microRNAs were assessed at baseline and after treatment.
Results
The results showed that the expression of miR-16, miR146-a and IL-4 levels in patients with asthma after receiving probiotic supplementation was significantly reduced and miR-133b expression was increased. In addition, pulmonary function tests showed a significant improvement in Forced Expiratory Volume in 1 s and Forced Vital Capacity after receiving probiotics.
Conclusion
In our study, 8-week treatment with probiotic supplementation led to reduced Th2 cells-associated IL-4 and improved Forced Expiratory Volume and Forced Vital Capacity. It appears probiotics can be used in addition to common asthma treatments.
... The 'hygiene hypothesis' was first presented in 1989 and proposed that declining microbial exposure is a major causative factor in the increasing incidence of atopy in recent years. The microbial hypothesis can be considered as a potential underlying mechanism of high prevalence, which argues that less microbial exposure regulates the production of T-helper cell type 2 (Th2)-related cytokines, leads to an increase allergic diseases (3,4). It has been reported that allergic asthma is tightly associated with imbalance of Th1/Th2 cells and their characteristic cytokine profiles (5). ...
Introduction: Asthma is known as one of the most common chronic inflammatory diseases characterized by recurrent obstruction and inflammation of the airways. Probiotics are defined as a group of beneficial living microorganisms that are beneficial in many disorders, including allergies. The aim of this study was to investigate the probiotic supplement effects on improvement of clinical asthma symptom and changes in the pattern of Th17-related inflammatory cytokines in asthmatic patients.
Methods: This was a randomized controlled clinical trial with parallel, double-blind groups. Forty patients with asthma were enrolled and received 1 capsule/day of a probiotic supplement for 8 weeks. Respiratory function tests; and the level of IL-6, IL-17, IL-21 and TGF-β were evaluated at the baseline and end of intervention.
Results: The results showed that the level of IL-6 and IL-17 in patients after receiving probiotics was reduced and expression of TGF-β was increased as compared to the baseline. Also, the expression of IL-17 and IL-21 in the probiotic group was significantly lower than the placebo group at the end of the intervention. In addition, an improvement in pulmonary function tests and clinical symptoms was observed after receiving probiotics.
Conclusion: Eight-weeks treatment with a probiotic supplementation suggests that it may effect on Th17 cells-associated IL-6, IL-17 and TGF-β; and Forced Expiratory Volume in 1 second and Forced Vital Capacity. Taken together, these results suggest that probiotics may have the ability to affect neutrophilic asthma and they can possibly be used besides common treatments for patients with neutrophilic asthma.
... 178,223 Two metagenomic studies conducted in South Korea analyzed fecal samples of patients with AD and revealed a decreased abundance in Faecalibacterium prausnitzii along with a significant reduction in SCFA production when compared with healthy controls. 2,179,180 According to a study, dysbiosis of F. prausnitzii in patients with AD was associated with an increased expression of a variety of nutrients. These nutrients, such as the mucin components GalNAc and L-fucose, are released from damaged gut epithelium, indicating a leaky gut and dysregulation of inflammation of the gut epithelium. ...
The human intestine hosts diverse microbial communities that play a significant role in maintaining gut-skin homeostasis. When the relationship between gut microbiome and the immune system is impaired, subsequent effects can be triggered on the skin, potentially promoting the development of skin diseases. The mechanisms through which the gut microbiome affects skin health are still unclear. Enhancing our understanding on the connection between skin and gut microbiome is needed to find novel ways to treat human skin disorders. In this review, we systematically evaluate current data regarding microbial ecology of healthy skin and gut, diet, pre- and probiotics, and antibiotics, on gut microbiome and their effects on skin health. We discuss potential mechanisms of the gut-skin axis and the link between the gut and skin-associated diseases, such as psoriasis, atopic dermatitis, acne vulgaris, rosacea, alopecia areata, and hidradenitis suppurativa. This review will increase our understanding of the impacts of gut microbiome on skin conditions to aid in finding new medications for skin-associated diseases.
... The role of the microbiota in AD development has been explained by the microbiota hypothesis, which states that a modern lifestyle reduces exposure to microorganisms and alters the microbiota composition, which, in turn, leads to the incomplete development of the immune system and favors allergy development [130,131]. The establishment of ID preceding the development of this disease is evidence to support this theory, as decreased Probiotics help restore the balance through the increase in anti-inflammatory metabolites, such as SCFAs, immune cells, such as Treg lymphocytes, and cytokines, such as IL-10, to reduce and control the inflammation produced during these cutaneous pathologies: SCFAs, short-chain fatty acids; APC, antigen-presenting cell. ...
... The role of the microbiota in AD development has been explained by the microbiota hypothesis, which states that a modern lifestyle reduces exposure to microorganisms and alters the microbiota composition, which, in turn, leads to the incomplete development of the immune system and favors allergy development [130,131]. The establishment of ID preceding the development of this disease is evidence to support this theory, as decreased microbial diversity and colonization by pathogens such as Escherichia coli and Clostridium difficile at a young age is associated with increased AD risk in infants [132][133][134][135][136]. ...
The gut microbiota (GM) comprises billions of microorganisms in the human gastrointestinal tract. This microbial community exerts numerous physiological functions. Prominent among these functions is the effect on host immunity through the uptake of nutrients that strengthen intestinal cells and cells involved in the immune response. The physiological functions of the GM are not limited to the gut, but bidirectional interactions between the gut microbiota and various extraintestinal organs have been identified. These interactions have been termed interorganic axes by several authors, among which the gut–brain, gut–skin, gut–lung, gut–heart, and gut–metabolism axes stand out. It has been shown that an organism is healthy or in homeostasis when the GM is in balance. However, altered GM or dysbiosis represents a critical factor in the pathogenesis of many local and systemic diseases. Therefore, probiotics intervene in this context, which, according to various published studies, allows balance to be maintained in the GM, leading to an individual’s good health.
... Probiotics also regulate the adaptive immune system by increasing the ratio of regulatory to effector T-cells. 56 The suggested mechanism of increase in the T regulatory (Treg) cells occurs through induction of regulatory DCs. The upregulation of Treg cells occurs simultaneously with suppression of effector cells such as T-helper Th1, Th2, and Th17. ...
Immunity is protective mechanism of the body against infection, diseases, and cancers. The stronger the immunity is the healthier we are. With increasing environmental change worldwide, increase of new emerging diseases and infection over last few decades, it has become imperative to move toward prevention more than the treatment. The immune mechanism in pediatric population especially neonates and infants is much different than adults and is yet evolving. The development of immunity starts in utero and is dependent on several factors. The various efforts to improve immunity and health should start from antenatal period focusing on overall health and nutrition of mother. Maternal nutrition, antenatal steroids, and delayed cord clamping are helpful in decreasing various neonatal morbidities which include respiratory distress syndrome, sepsis, necrotizing enterocolitis, intraventricular hemorrhage, and mortality. After birth during initial 6 months, exclusive breastfeeding, growth monitoring, primary immunization, developmentally supportive care, and care of infections are of utmost importance. After 6 months of age, a balanced approach toward introduction of complementary feeding, care of micronutrients, optimal environment, and inclusion of immunity enhancing foods in diet may have considerable benefits.
... TSLP-activated DCs prime naïve Th cells to produce the proallergic cytokines IL-4, IL-5, and IL-13, while downregulating IL-10. 33 The expression levels of TSLP, MDC, and TARC were elevated in DFE +PBS mice but reduced in KBL382-treated mice, which may suppress differentiation of T cells into Th2 cells and the secretion of Th2-type cytokines ( Figure 4). ...
Administration of probiotics has been linked to immune regulation and changes in gut microbiota composition, with effects on atopic dermatitis (AD). In this study, we investigated amelioration of the symptoms of AD using Lactobacillus paracasei KBL382 isolated from the feces of healthy Koreans. Mice with Dermatophagoides farinae extract (DFE)-induced AD were fed 1 × 109 CFU d-1 of L. paracasei KBL382 for 4 weeks. Oral administration of L. paracasei KBL382 significantly reduced AD-associated skin lesions, epidermal thickening, serum levels of immunoglobulin E, and immune cell infiltration. L. paracasei KBL382-treated mice showed decreased production of T helper (Th)1-, Th2-, and Th17-type cytokines, including thymic stromal lymphopoietin, thymus, and activation-regulated chemokine, and macrophage-derived chemokine, and increased production of the anti-inflammatory cytokine IL-10 and transforming growth factor-β in skin tissue. Intake of L. paracasei KBL382 also increased the proportion of CD4+ CD25+ Foxp3+ regulatory T cells in mesenteric lymph nodes. In addition, administration of L. paracasei KBL382 dramatically changed the composition of gut microbiota in AD mice. Administration of KBL382 significantly ameliorates AD-like symptoms by regulating the immune response and altering the composition of gut microbiota.
... Alternatively, certain pathogenic bacterial species may promote gut wall permeability leading to leakage of toxic and pro-inflammatory molecules 43 . In two metagenomic studies, presence of F. prausnitzii in the fecal samples of AD patients and concurrent decrease of SCFA, which is important in keeping the integrity of the epithelial barrier, have been suggested to lead to the 'leaky gut' in AD patients 49,50 . Others argued that it is a lack of bacterial diversity in the gut, rather than a presence of causative bacterial species, that impairs maturation of the immune system 51,52 . ...
The human microbiome is a rich environment consisting of bacteria, fungi and other commensal microorganisms of the gut, mucosa and skin. The functional role of the gut microbiome includes facilitation in metabolism of macronutrients, maturation of the immune system, and production of pro- or anti-inflammatory signaling molecules and peptides. The identification of these resident organisms has brought about a new understanding of disease processes. Nevertheless, more questions remain regarding the interactions within the microbiome, its interactions with the host, and its contributions to the pathophysiology of disease. The purpose of this review is to examine the existing medical literature to highlight the role of the gut microbiome in human health, also paying attention to its role in several inflammatory skin diseases, namely atopic dermatitis, psoriasis, and rosacea. Copyright © The Korean Dermatological Association and The Korean Society for Investigative Dermatology
... 14 In a novel mouse model study, probiotic administration may have prevented the development of AD by suppressing production of inflammatory cytokines, thymic stromal lymphopoietin (TSLP) and IL-4 by a mechanism that may involve CD4(+)CD25(+)Foxp3(+) T reg (regulatory T) cells in the skin. 15 TSLP is an epithelial-derived cytokine that is expressed by skin, lung and gut epithelial cells. Various cytokines, trauma and allergens are able to activate TSLP production. ...
Probiotic supplementation may decrease the risk of allergic disease; however, there are differences between studies, such as the type of probiotic, the route or the duration of supplementation. Therefore, determining the most effective probiotic strain/s, route of administration and duration for clinical recommendation has been difficult. An electronic systematic literature search was undertaken between using Ovid MEDLINE, Embase, PubMed and Cochrane. Risk ratio (RR) and 95% confidence interval (CI) are presented for the studies. PEDro scale and Newcastle–Ottawa Scale were used to assess the quality of the included studies. A total of 21 studies met the inclusion criteria. Strain‐specific sub‐meta‐analyses indicated that single strains are not as effective as probiotic mixtures and administration to a combination of pregnant mothers, breastfeeding mothers and infants had a reduced risk in the onset of atopic dermatitis in children. Our systematic review and meta‐analysis showed that a mixture of probiotic supplementation given to the mother in pregnancy and continuing while breastfeeding and also to the infant in children classified as high‐risk for atopic dermatitis and non‐high‐risk groups is the most efficacious in reducing the risk of incidence of atopic dermatitis in children.
