Lactobacillus sakei WIKIM30 Ameliorates Atopic Dermatitis-Like Skin Lesions by Inducing Regulatory T Cells and Altering Gut Microbiota Structure in Mice

Extracellular vesicles of Limosilactobacillus fermentum SLAM216 ameliorate skin symptoms of atopic dermatitis by regulating gut microbiome on serotonin metabolism

Atopic dermatitis (AD) is a globally prevalent chronic inflammatory skin disorder. Its pathogenesis remains incompletely understood, resulting in considerable therapeutic challenges. Recent studies have highlighted the significance of the interaction between AD and gut microbiome. In this study, we investigated the effects of probiotic-derived extracellular vesicles on AD. Initially, we isolated and characterized extracellular vesicles from Limosilactobacillus fermentum SLAM 216 (LF216EV) and characterized their composition through multi-omics analysis. Gene ontology (GO) and pathway analysis classified LF216EV proteins into biological processes, molecular functions, and cellular components. Importantly, specific abundance in linoleic, oleic, palmitic, sebacic, and stearic acids indicating upregulated fatty acid metabolism were observed by metabolomic analysis. Furthermore, featured lipid profiling including AcylGlcADG and ceramide were observed in LF216EV. Importantly, in an atopic dermatitis-like cell model induced by TNFα/IFNγ, LF216EV significantly modulated the expression of immune regulatory genes (TSLP, TNFα, IL-6, IL-1β, and MDC), indicating its potential functionality in atopic dermatitis. LF216EV alleviated AD-like phenotypes, such as redness, scaling/dryness, and excoriation, induced by DNCB. Histopathological analysis revealed that LF216EV decreased epidermal thickness and mast cell infiltration in the dermis. Furthermore, LF216EV administration reduced mouse scratching and depression-related behaviors, with a faster onset than the classical treatment with dexamethasone. In the quantitative real-time polymerase chain reaction (qRT-PCR) analysis, we observed a significant increase in the expression levels of htrb2c, sert, and tph-1, genes associated with serotonin, in the skin and gut of the LF216EV-treated group, along with a significant increase in the total serum serotonin levels. Gut microbiome analysis of the LF216EV-treated group revealed an altered gut microbiota profile. Correlation analysis revealed that the genera Limosilactobacillus and Desulfovibrio were associated with differences in the intestinal metabolites, including serotonin. Our findings demonstrate that LF216EV mitigates AD-like symptoms by promoting serotonin synthesis through the modulation of gut microbiota and metabolome composition.

Development and clinical assessment of a novel probiotic candy in the prevention of respiratory infections in asthmatic children

Objective

Asthma is the most common chronic disease among children. Upper respiratory infections are often the cause of asthma exacerbation. Studies suggested that spore-forming probiotics can reduce viral infections. This study aimed to determine the effect of spore-forming probiotic Bacillus candy on respiratory illnesses in asthmatic children.

Methods & materials

In this randomized trial, 69 children aged 7-11 years with mild intermittent asthma were randomized to receive probiotic candy (containing 1010 CFU probiotic Bacillus coagulans) or placebo candy, daily for 2 months. The primary outcome was the number of viral respiratory infections. Secondary outcomes included salbutamol metered-dose inhaler (MDI) use, oral corticosteroids, school absenteeism, emergency department visits and hospitalizations, and Pediatric Asthma Control Questionnaire (c-ACT).

Results

The frequency of symptomatic respiratory illnesses was significantly lower in the probiotic candy group compared to placebo in the first month (0.28 ± 0.45 vs. 0.51 ± 0.50, p = 0.054), the second month (0.08 ± 0.28 vs. 0.41 ± 0.49, p = 0.001) and the total study (0.37 ± 0.54 vs. 0.90 ± 0.73, 0.001). The percent of patients with prednisolone consumption in the probiotic group was lower than the control group (2.9% vs. 14.7%) but did not show a significant difference (p = 0.081) and no difference was seen in the rate of emergency department visits and hospitalization between the 2 groups (both p = 0.254). The use of salbutamol and school absenteeism in the probiotic group was significantly lower than in the control group (p = 0.040 and p = 0.046, respectively. There was no significant difference in the evaluated scores for asthma control (c-ACT) in both probiotic and placebo groups. After the intervention, the difference between the 2 groups has become significant (p < 0.05).

Conclusion

Adding spore-forming probiotic candy containing Bacillus coagulans to standard asthma treatments reduced symptomatic respiratory illnesses over two months. Further studies including longer treatment periods are needed before making recommendations for routine use.

Lactobacillus helveticus attenuates alcoholic liver injury via regulation of gut microecology in mice

Previous reports have demonstrated that alcohol consumption significantly reduces the abundance of Lactobacillus in the gut. In this study, we selected five species of the genus Lactobacillus, commonly found in fermented foods, and acknowledged them as safe, edible, and effective in preventing or treating certain diseases, to evaluate their effects on alcoholic liver disease (ALD). By comparing the liver damage indices in each group, we found that the type strain of Lactobacillus helveticus (LH, ATCC 15009) had the most marked alleviating effect on ALD-induced liver injury. Furthermore, experiments combining microbiomics and metabolomics were conducted to explore the mechanisms underlying the hepatoprotective effects of LH. Finally, we discovered that LH mitigated ethanol-induced liver steatosis and inflammation in ALD mice by altering the structure and function of the gut microbiome, increasing intestinal levels of short-chain fatty acids (SCFAs), and enhancing gut barrier integrity. These findings suggest a potential strategy for the clinical management of patients with ALD.

Effect of Staphylococcus aureus colonization and immune defects on the pathogenesis of atopic dermatitis

Atopic dermatitis (AD) is a common and recurrent skin disease characterized by skin barrier dysfunction, inflammation and chronic pruritus, with wide heterogeneity in terms of age of onset, clinical course and persistence over the lifespan. Although the pathogenesis of the disease are unclear, epidermal barrier dysfunction, immune and microbial dysregulation, and environmental factors are known to be critical etiologies in AD pathology. The skin microbiota represents an ecosystem consisting of numerous microbial species that interact with each other as well as host epithelial cells and immune cells. Although the skin microbiota benefits the host by supporting the basic functions of the skin and preventing the colonization of pathogens, disruption of the microbial balance (dysbiosis) can cause skin diseases such as AD. Although AD is a dermatological disease, recent evidence has shown that changes in microbiota composition in the skin and intestine contribute to the pathogenesis of AD. Environmental factors that contribute to skin barrier dysfunction and microbial dysbiosis in AD include allergens, diet, irritants, air pollution, epigenetics and microbial exposure. Knowing the microbial combination of intestin, as well as the genetic and epigenetic determinants associated with the development of autoantibodies, may help elucidate the pathophysiology of the disease. The skin of patients with AD is characterized by microbial dysbiosis as a result of reduced microbial diversity and overgrowth of the pathogens such as Staphylococcus aureus. Recent studies have revealed the importance of building a strong immune response against microorganisms during childhood and new mechanisms of microbial community dynamics in modulating the skin microbiome. Numerous microorganisms are reported to modulate host response through communication with keratinocytes, specific immune cells and adipocytes to improve skin health and barrier function. This growing insight into bioactive substances in the skin microbiota has led to novel biotherapeutic approaches targeting the skin surface for the treatment of AD. This review will provide an updated overview of the skin microbiota in AD and its complex interaction with immune response mechanisms, as well as explore possible underlying mechanisms in the pathogenesis of AD and provide insights into new therapeutic developments for the treatment of AD. It also focuses on restoring skin microbial homeostasis, aiming to reduce inflammation by repairing the skin barrier.

The Skin Histopathology of Pro- and Parabiotics in a Mouse Model of Atopic Dermatitis

As it has been revealed that the activation of human immune cells through the activity of intestinal microorganisms such as pro- and prebiotics plays a vital role, controlling the proliferation of beneficial bacteria and suppressing harmful bacteria in the intestine has become essential. The importance of probiotics, especially for skin health and the immune system, has led to the emergence of products in various forms, including probiotics, prebiotics, and parabiotics. In particular, atopic dermatitis (AD) produces hypersensitive immunosuppressive substances by promoting the differentiation and activity of immune regulatory T cells. As a result, it has been in the Th1 and Th2 immune balance through a mechanism that suppresses skin inflammation or allergic immune responses caused by bacteria. Furthermore, an immune mechanism has recently emerged that simultaneously controls the expression of IL-17 produced by Th17. Therefore, the anti-atopic effect was investigated by administering doses of anti-atopic candidate substances (Lactobacilus sakei CVL-001, Lactobacilus casei MCL, and Lactobacilus sakei CVL-001 Lactobacilus casei MCL mixed at a ratio of 4:3) in an atopy model using 2,4-dinitrochlorobenzene and observing symptom changes for 2 weeks to confirm the effect of pro-, para-, and mixed biotics on AD. First, the body weight and feed intake of the experimental animals were investigated, and total IgG and IgM were confirmed through blood biochemical tests. Afterward, histopathological staining was performed using H&E staining, Toluidine blue staining, Filaggrin staining, and CD8 antibody staining. In the treatment group, the hyperproliferation of the epidermal layer, the inflammatory cell infiltration of the dermal layer, the expression of CD8, the expression of filaggrin, and the secretion of mast cells were confirmed to be significantly reduced. Lastly, small intestine villi were observed through a scanning microscope, and scoring evaluation was performed through skin damage. Through these results, it was confirmed that AD was reduced when treated with pro-, para-, and mixed biotics containing probiotics and parabiotics.

Daily Supplementation with Bifidobacterium longum KACC91563 Alleviates Allergic Contact Dermatitis in an Animal Model

Allergic contact dermatitis (ACD) is the most common chronic inflammatory skin disease (or immune-mediated disease), causing disruption to our psychological condition and life quality. In this study, the therapeutic properties of probiotic Bifidobacterium longum (B. longum) was investigated by using an ACD-induced animal model. For ACD induction, BALB/c mice ear and dorsal skin were sensitized with 240 µL of 1% (w/v) 2,4-dinitrochlorobenzene (DNCB) twice (3-day intervals). After a week of the first induction, the mice were re-sensitized by painting on their dorsal skin and ear with 0.4% (w/v) DNCB for a further three times (once per week). Before the ACD induction of 2 weeks and throughout the trial period, the BALB/c mice were supplemented daily with 1 mL of 1.0 × 109 CFU or 5.0 × 109 CFU B. longum using an intragastric gavage method. The ACD-induced mice without B. longum supplementation were used as a control. Results show that B. longum supplementation significantly alleviated ACD symptoms (e.g., ear swelling, epidermal damage) and immune response (e.g., reduced immune cell recruitment, serum IgE level, and cytokine production). The therapeutic efficiency of B. longum increased as the supplementation dose increased. Thus, daily supplementation with 5.0 × 109 CFU probiotic B. longum could be an effective method for the prevention and treatment of ACD.

Pediococcus pentosaceus KF159 alleviates house dust mite-induced atopic dermatitis by promoting IL10 production and regulatory T cell induction

Atopic dermatitis (AD) is a chronic immune disease that requires long-term management owing to its relative ease of recurrence. However, steroid treatment is limited owing to the side effects. Therefore, research on therapeutics with proven safety is required. Here, we evaluated the anti-allergic activity of the probiotic strain Pediococcus pentosaceus KF159 (PPKF159) with an ex vivo mouse model sensitized with ovalbumin (OVA) and a mouse model of AD induced by house dust mites. Changes in pathological symptoms were confirmed based on the clinical status of the AD-induced lesion site and the levels of T helper type 2 (Th2)-derived cytokines and immunoglobulin E (IgE). In addition, cell-mediated responses and related mechanisms were elucidated using various kinds of primary cells including splenocytes, mesenteric lymph nodes, Peyer's patch, and bone marrow-derived dendritic cells (BMDCs) in vitro and ex vivo. Oral administration of PPKF159 alleviated AD-like clinical symptoms such as erythema, edema, hemorrhage, and increased tissue thickness, and suppressed the production of Th2-associated cytokines and serum IgE while increasing T helper type 1 (Th1)-mediated cytokine production. PPKF159 induced tolerogenic dendritic cells (tol-DCs) by increasing the expression of ICOS-L, PD-L1, and IDO which were closely related to Treg induction in PPKF159-treated BMDCs. In addition, BMDCs and naive T cells co-cultured in the presence of PPKF159 had elevated IL10 production and increased proportions of CD4+CD25+Foxp3+ Tregs compared to the absence of PPKF159. This study showed that PPKF159 relieved AD-like clinical symptoms, modulated the Th1/Th2 immune balance, and inhibited IgE production in a mouse AD model. PPKF159 induced the transformation of dendritic cells into tolerogenic versions. These induced tol-DCs directly enhanced the production of IL10 or improved the secretion of IL10 through the induction of CD4+CD25+Foxp3+ Treg cells, thereby improving AD. These results suggest that PPKF159 can be applied as a functional food material for the treatment and prevention of AD.

Effect of Mixed Probiotics on Ovalbumin-Induced Atopic Dermatitis in Juvenile Mice

Atopic dermatitis is one of the most common dermatologic problems, especially in children. Given the ability of symbiotic microorganisms in modulating the immune system, probiotics administration has been studied in previous research in the management of atopic dermatitis. However, there are conflicting results between studies. In this study, we aimed to assess the effectiveness of mixed probiotics as a treatment option for atopic dermatitis induced by ovalbumin. BALB/c juvenile mice were classified and divided into the ovalbumin group, mixed probiotic group (ovalbumin + LK), and control group. Except for the control group, all mice were sensitized with ovalbumin to establish a model of atopic dermatitis. The mixed probiotics were given by gavage for 14 days. Mice body weight, skin lesions, skin inflammation, ovalbumin-specific Ig, the number of Treg and CD103+DC, and the expression level of PD-1/PD-L1 were examined. The results showed that mixed probiotics can improve body weight and alleviate skin symptoms. Mixed probiotics reduced serum Th2 inflammatory factors, eosinophils, mast cell degranulation, mast cell count, and the expression of ovalbumin-specific immunoglobulin E/G1 and increased the anti-inflammatory cytokine interleukin-10, Treg cells, CD103+DC cells, and the expression level of PD-1/PD-L1. These findings suggest that mixed probiotics could be a viable treatment option for atopic dermatitis and provide insight into the underlying mechanisms involved.

The causal relationship between gut microbiota and immune skin diseases: A bidirectional Mendelian randomization

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 microbiota, 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 microbiota 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 five associated genera in the psoriasis group, seven associated genera were obtained in the atopic dermatitis group, a total of ten associated genera in the acne group, and four associated genera in the lichen planus group. The results corrected for false discovery rate showed that Eubacteriumfissicatenagroup (P = 2.20E-04, OR = 1.24, 95%CI:1.11-1.40) and psoriasis 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 gut microbiota.

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.

Effects of dietary N-carbamylglutamate supplementation on the modulation of microbiota and Th17/Treg balance-related immune signaling after lipopolysaccharide challenge

BACKGROUND

This study aimed to evaluate the effects of N-carbamylglutamate (NCG) on piglets' growth performance and immune response, and to unravel the mechanisms of such effects. In a 2 × 2 factorial design including diet (with or without NCG) and immunological challenge (saline or lipopolysaccharide (LPS)), 24 piglets were randomly distributed into four groups. After being fed a basic diet or a NCG-supplemented diet for 21 days, piglets were administered LPS or saline intraperitoneally.

RESULTS

The results showed that NCG increased the average daily gain and average daily feed intake, and the feed conversion ratio of piglets, and alleviated the adverse effects of LPS stimulation on intestinal morphology. At the phylum level, NCG reversed the increase in the abundance of Firmicutes and the reduction in that of Actinomycete caused by LPS stimulation. At the genus level, NCG increased the abundance of Lactobacillus, Blautia, norank_Butyricicoccaceae, Subdoligranulum, and Ruminococcus_gauvreauii_group, and LPS decreased the abundance of Escherichia-Shigella and Ruminococcus_gauvreauii_group. The short-chain fatty acid content was increased by NCG, but LPS reduced its content. N-Carbamylglutamate also inhibited significantly the LPS-induced increase in the relative expression of signal transducer and activator of transcription (STAT) 3, related orphan receptor (RAR) c, and pro-inflammatory cytokines, and the decrease in the relative expression of STAT5, forkhead box P3, IL-10 and transforming growth factor beta 1 mRNA. A significant correlation was found between intestinal microbiota and inflammatory cytokines and short-chain fatty acids.

CONCLUSION

N-Carbamylglutamate can improve piglets' growth performance. It can also attenuate LPS-induced intestinal inflammation by modulating microbiota and Th17/Treg balance-related immune signaling pathways. © 2023 Society of Chemical Industry.

Therapeutic effects of the Qingre-Qushi recipe on atopic dermatitis through the regulation of gut microbiota and skin inflammation

Accumulating evidence has highlighted a strong association between gut microbiota and the occurrence, development, prevention, and treatment of atopic dermatitis (AD). The regulation of gut microbial dysbiosis by oral traditional Chinese medicine (TCM) has garnered significant attention. In the treatment of AD, the TCM formula Qingre-Qushi Recipe (QRQS) has demonstrated clinical efficacy. However, both the therapeutic mechanisms of QRQS and its impact on gut microbiota remain unclear. Thus, our study aimed to assess the efficacy of QRQS and evaluate its influence on the composition and diversity of gut microbiota in AD animal models. First, we investigated the therapeutic effect of QRQS on AD using two animal models: filaggrin-deficient mice (Flaky tail, ft/ft) and MC903-induced AD-like mice. Subsequently, we explored its influence on the composition and diversity of gut microbiota. Our results demonstrated that QRQS treatment ameliorated the symptoms in both ft/ft mice and MC903-induced AD-like mice. It also reduced the levels of serum IgE and pro-inflammatory cytokines, including IL-1β, IL-4, IL-5, IL-9, IL-13, IL-17A, and TNF-α. Furthermore, QRQS remarkably regulated gut microbiota diversity by increasing Lactobacillaceae and decreasing Bacteroidales. The inflammatory factors in peripheral serum of ft/ft mice showed a close correlation with gut microbiota, as determined using the Spearman correlation coefficient. Additionally, PICRUSt analysis revealed an enrichment in ascorbate and aldarate metabolism, fatty acid metabolism and biosynthesis, and propanoate metabolism in the QRQS group compared to the ft/ft group. Finally, we identified liquiritin as the primary active ingredient of QRQS using ultra-high-performance liquid chromatography-high-resolution mass spectrometry (UPLC-HRMS). Our findings revealed that QRQS improved AD-like symptoms and alleviated skin inflammation in ft/ft and MC903-induced mice. This suggests that modulating the gut microbiota may help elucidate its anti-inflammation activation mechanism, highlighting a new therapeutic strategy that targets the intestinal flora to prevent and treat AD.

Tryptophan, an important link in regulating the complex network of skin immunology response in atopic dermatitis

Atopic dermatitis (AD) is a common chronic relapsing inflammatory skin disease, of which the pathogenesis is a complex interplay between genetics and environment. Although the exact mechanisms of the disease pathogenesis remain unclear, the immune dysregulation primarily involving the Th2 inflammatory pathway and accompanied with an imbalance of multiple immune cells is considered as one of the critical etiologies of AD. Tryptophan metabolism has long been firmly established as a key regulator of immune cells and then affect the occurrence and development of many immune and inflammatory diseases. But the relationship between tryptophan metabolism and the pathogenesis of AD has not been profoundly discussed throughout the literatures. Therefore, this review is conducted to discuss the relationship between tryptophan metabolism and the complex network of skin inflammatory response in AD, which is important to elucidate its complex pathophysiological mechanisms, and then lead to the development of new therapeutic strategies and drugs for the treatment of this frequently relapsing disease.

Emerging Role of the Mast Cell-Microbiota Crosstalk in Cutaneous Homeostasis and Immunity

The skin presents a multifaceted microbiome, a balanced coexistence of bacteria, fungi, and viruses. These resident microorganisms are fundamental in upholding skin health by both countering detrimental pathogens and working in tandem with the skin's immunity. Disruptions in this balance, known as dysbiosis, can lead to disorders like psoriasis and atopic dermatitis. Central to the skin's defense system are mast cells. These are strategically positioned within the skin layers, primed for rapid response to any potential foreign threats. Recent investigations have started to unravel the complex interplay between these mast cells and the diverse entities within the skin's microbiome. This relationship, especially during times of both balance and imbalance, is proving to be more integral to skin health than previously recognized. In this review, we illuminate the latest findings on the ties between mast cells and commensal skin microorganisms, shedding light on their combined effects on skin health and maladies.

Lipid mediators derived from DHA alleviate DNCB-induced atopic dermatitis and improve the gut microbiome in BALB/c mice

Atopic dermatitis (AD) is a chronic inflammatory skin condition that primarily results from immune dysregulation. We determined the potential therapeutic benefits of lipid mediators (LM, 17S-monohydroxy DHA, resolvin D5, and protectin DX in a ratio of 3:47:50) produced by soybean lipoxygenase from DHA. The underlying molecular mechanisms involved in TNF-α/IFN-γ-stimulated HaCaT cells as well as its effect in an AD mouse model induced by DNCB in BALB/c mice were examined. The results indicated that LM effectively attenuates the production of inflammatory cytokines (IL-6 and IL-1β) and chemokines (IL-8 and MCP-1) by inhibiting the NF-κB signaling pathway in TNF-α/IFN-γ-stimulated HaCaT cells. The oral administration of LM at 5 or 10 μg/kg/day significantly reduced skin lesions, epidermal thickness, and mast cell infiltration in AD mice. Furthermore, LM reduced the production of IgE and inflammatory cytokines (TNF-α, IL-6, and IL-1β) in the serum, modulated gut microbiota diversity, and restored the microbial composition. Overall, our findings suggest that LM represents a potential therapeutic agent for improving AD symptoms through its ability to suppress inflammatory cytokines and alter the composition of gut microbiota.

Exploring the Association between Gut Microbiota and Inflammatory Skin Diseases: A Two-Sample Mendelian Randomization Analysis

Emerging research underscores the substantial link between gut flora and various inflammatory skin diseases. We hypothesize that there exists a complex gut-skin axis, possibly affecting the progression of conditions such as eczema, acne, psoriasis, and rosacea. However, the precise nature of the causal connection between gut flora and skin diseases remains unestablished. In this study, we started by compiling summary data from genome-wide association studies (GWAS) featuring 211 unique gut microbiota and four types of skin conditions. We scrutinized these data across different taxonomic strata. Subsequently, we leveraged Mendelian randomization (MR) to ascertain if there is a causal link between gut microbiota and these skin conditions. We also performed a bidirectional MR analysis to identify the causality's direction. By utilizing Mendelian randomization, we identified 26 causal connections between the gut microbiome and four recognized inflammatory skin conditions, including 9 positive and 17 negative causal directions. Additional sensitivity analyses of these results revealed no evidence of pleiotropy or heterogeneity. Our MR analysis suggests a causal connection between gut microbiota and skin diseases, potentially providing groundbreaking perspectives for future mechanistic and clinical studies on microbiota-affected skin conditions.

Evaluation of Different Activity of Lactobacillus spp. against Two Proteus mirabilis Isolated Clinical Strains in Different Anatomical Sites In Vitro: An Explorative Study to Improve the Therapeutic Approach

Urinary tract infections (UTIs) and catheter-associated UTIs (CAUTIs) are the principal hospital-acquired infections. Between these, bacterial prostatitis is believed to be the leading cause of recurrent UTIs in men under 50 years of age and is often unresponsive to antibiotic treatment. Proteus mirabilis is more commonly associated with UTIs in these abnormalities, especially in patients undergoing catheterization. Lactobacillus spp. are an important component of the human microbiota and occur in large quantities in foods. Probiotics are proposed as an alternative to antibiotic therapy in the treatment of urinary tract infections. In addition to their ability to produce antimicrobial metabolites, they have immunomodulatory activity and do not cause side effects. For this reason, the combination of probiotic microorganisms and conventional drugs was considered. The aim of this work was to select the most active Lactobacillus strains against two clinical isolates of P. mirabilis on bladder and prostatic epithelium, potentially exploitable to improve the clinical management of UTIs.

From gut to skin: exploring the potential of natural products targeting microorganisms for atopic dermatitis treatment

Atopic dermatitis (AD) is the most common chronic inflammatory skin disease. Recent studies have revealed that interactions between pathogenic microorganisms, which have a tendency to parasitize the skin of AD patients, play a significant role in the progression of the disease. Furthermore, specific species of commensal bacteria in the human intestinal tract can have a profound impact on the immune system by promoting inflammation and pruritogenesis in AD, while also regulating adaptive immunity. Natural products (NPs) have emerged as promising agents for the treatment of various diseases. Consequently, there is growing interest in utilizing natural products as a novel therapeutic approach for managing AD, with a focus on modulating both skin and gut microbiota. In this review, we discuss the mechanisms and interplay between the skin and gut microbiota in relation to AD. Additionally, we provide a comprehensive overview of recent clinical and fundamental research on NPs targeting the skin and gut microbiota for AD treatment. We anticipate that our work will contribute to the future development of NPs and facilitate research on microbial mechanisms, based on the efficacy of NPs in treating AD.

Bacterial Metabolites and Inflammatory Skin Diseases

The microbiome and gut-skin axis are popular areas of interest in recent years concerning inflammatory skin diseases. While many bacterial species have been associated with commensalism of both the skin and gastrointestinal tract in certain disease states, less is known about specific bacterial metabolites that regulate host pathways and contribute to inflammation. Some of these metabolites include short chain fatty acids, amine, and tryptophan derivatives, and more that when dysregulated, have deleterious effects on cutaneous disease burden. This review aims to summarize the knowledge of wealth surrounding bacterial metabolites of the skin and gut and their role in immune homeostasis in inflammatory skin diseases such as atopic dermatitis, psoriasis, and hidradenitis suppurativa.

Microbiota and IL-33/31 Axis Linkage: Implications and Therapeutic Perspectives in Atopic Dermatitis and Psoriasis

Microbiome dysbiosis and cytokine alternations are key features of atopic dermatitis (AD) and psoriasis (PsO), two of the most prevalent and burdensome pruritic skin conditions worldwide. Interleukin (IL)-33 and IL-31 have been recognized to be major players who act synergistically in the pathogenesis and maintenance of different chronic inflammatory conditions and pruritic skin disorders, including AD and PsO, and their potential role as therapeutic targets is being thoroughly investigated. The bidirectional interplay between dysbiosis and immunological changes has been extensively studied, but there is still debate regarding which of these two factors is the actual causative culprit behind the aetiopathological process that ultimately leads to AD and PsO. We conducted a literature review on the Pubmed database assessing articles of immunology, dermatology, microbiology and allergology with the aim to strengthen the hypothesis that dysbiosis is at the origin of the IL-33/IL-31 dysregulation that contributes to the pathogenesis of AD and PsO. Finally, we discussed the therapeutic options currently in development for the treatment of these skin conditions targeting IL-31, IL-33 and/or the microbiome.

Effect of Lactobacillus sakei OK67 in Reducing Body and Visceral Fat in Lifestyle-Modified Overweight Individuals: A 12-Week, Randomized, Double-Blind, Placebo-Controlled Clinical Trial

Obesity is a global health problem that affects the quality of life. It is a multidimensional chronic risk factor for major medical conditions, such as cardiovascular diseases, diabetes, and cancer. This clinical trial evaluated the efficacy of Lactobacillus sakei OK67 (DW2010), a lactic acid bacterium, in reducing body and visceral fat in overweight individuals (body mass index ≥25 kg/m² and <30 kg/m²), aged 20-60 years. A total of 100 subjects placed in a lifestyle modification program were randomly assigned to receive either DW2010 (2.0 g/day, 1.0 × 10¹⁰ CFU) or a placebo for 12 weeks. The efficacy of DW2010 was evaluated by measuring body fat mass using dual-energy X-ray absorptiometry and visceral fat area using computed tomography. After 12 weeks, the change in body fat in the DW2010 group was not markedly different from that in the placebo group. However, visceral fat area decreased more in the DW2010 group than in the placebo group (p = 0.035). During the clinical trial, no major adverse events were reported. Moreover, no statistical differences were observed in the biochemical parameters of the DW2010 and placebo groups. Overall, we concluded that the intake of DW2010 for 12 weeks is safe and potentially reduces visceral fat in lifestyle-modified overweight subjects.

A Review on Maternal and Infant Microbiota and Their Implications for the Prevention and Treatment of Allergic Diseases

Allergic diseases, which are closely related to the composition and metabolism of maternal and infant flora, are prevalent in infants worldwide. The mother's breast milk, intestinal, and vaginal flora directly or indirectly influence the development of the infant's immune system from pregnancy to lactation, and the compositional and functional alterations of maternal flora are associated with allergic diseases in infants. Meanwhile, the infant's own flora, represented by the intestinal flora, indicates and regulates the occurrence of allergic diseases and is altered with the intervention of allergic diseases. By searching and selecting relevant literature in PubMed from 2010 to 2023, the mechanisms of allergy development in infants and the links between maternal and infant flora and infant allergic diseases are reviewed, including the effects of flora composition and its consequences on infant metabolism. The critical role of maternal and infant flora in allergic diseases has provided a window for probiotics as a microbial therapy. Therefore, the uses and mechanisms by which probiotics, such as lactic acid bacteria, can help to improve the homeostasis of both the mother and the infant, and thereby treat allergies, are also described.

Oral Administration of Lactobacillus sakei CVL-001 Improves Recovery from Dextran Sulfate Sodium-Induced Colitis in Mice by Microbiota Modulation

Inflammatory bowel disease (IBD) is an intestinal chronic inflammatory disease, and its incidence is steadily increasing. IBD is closely related to the intestinal microbiota, and probiotics are known to be a potential therapeutic agent for IBD. In our study, we evaluated the protective effect of Lactobacillus sakei CVL-001, isolated from Baechu kimchi, on dextran sulfated sodium (DSS)-induced colitis in mice. The oral administration of L. sakei CVL-001 according to the experimental schedule alleviated weight loss and disease activity in the mice with colitis. Furthermore, the length and histopathology of the colon improved. The expression of tumor necrosis factor (TNF)-α and interleukin (IL)-1β genes decreased in the colons of mice that were administered L. sakei CVL-001, whereas that of IL-10 increased. The expressions of genes coding for E-cadherin, claudin3, occludin, and mucin were also restored. In co-housed conditions, L. sakei CVL-001 administration did not improve disease activity, colon length, and histopathology. Microbiota analysis revealed that L. sakei CVL-001 administration increased the abundance of microbiota and altered Firmicutes/Bacteroidetes ratio, and decreased Proteobacteria. In conclusion, L. sakei CVL-001 administration protects mice from DSS-induced colitis by regulating immune response and intestinal integrity via gut microbiota modulation.

Therapeutic and Preventive Effect of Orally Administered Prebiotics on Atopic Dermatitis in a Mouse Model

PURPOSE

Recently, interest is increasing in using prebiotics, which are nutrient ingredients of live microorganism that improve the intestinal environments by promoting the growth of beneficial gut microflora. Although numerous studies have demonstrated the beneficial effects of probiotics on atopic dermatitis (AD) development, few have examined preventive and therapeutic effects of prebiotics on the onset and progression of AD.

METHODS

In this study, we investigated therapeutic and preventive effect of prebiotics, including β-glucan and inulin, using an oxazolone (OX)-induced AD-like mouse model. Prebiotics were orally administered 2 weeks after the end of sensitization period (therapeutic study) and 3 weeks before the initial sensitization (prevention study). The physiological and histological alterations in the skin and gut of the mice were investigated.

RESULTS

In the therapeutic study, the severity of skin lesions and inflammatory responses were effectively reduced after administering β-glucan and inulin, respectively. The expression level of calprotectin was significantly decreased by approximately 2-fold (P < 0.05) in the skin and gut of prebiotics-treated mice compared to the control. In addition, epidermal thickness and the number of infiltrated immune cells were markedly reduced in the dermis of prebiotics-treated mice compared <strike>with</strike> to those in the OX-induced mice (P < 0.05). These findings were same as in the prevention study. Importantly, pre-administration of β-glucan and inulin prevented the progression of AD by promoting the growth of good bacteria in the gut of OX-induced AD mice. However, the co-administration of β-glucan and inulin did not show enhanced preventive effects on these alterations.

CONCLUSIONS

Prebiotics has a therapeutic effect on AD in OX-induced AD mouse model. Moreover, our study suggests that prebiotics prevents the development of AD and this effect is associated with a change in gut microbiome.

Modulation of allergic contact dermatitis via gut microbiota modified by diet, vitamins, probiotics, prebiotics, and antibiotics

Allergic contact dermatitis is one of the most common recorded occupational diseases. There are many different substances that the skin comes into contact with on a daily basis and that can cause ACD, e.g., preservatives, surfactants, and antimicrobial agents. The development of a mouse model of ACD has provided insight into the immune mechanisms involved. Drugs used in the treatment of skin diseases have many side effects. Therefore, alternative methods of suppressing the immune response to reduce the symptoms of skin diseases are being sought. In recent years, high hopes have been placed on dietary modulation and supplementation to affect the intestinal microbial composition and promote anti-inflammatory responses. In addition, other studies have shown the crucial role of intestinal microbiota in many immune-mediated diseases. Recognition and characterization of pro- and anti-inflammatory nutrients and supplements may be crucial to support the treatment of diseases such as atopic dermatitis, acne vulgaris, psoriasis, and allergic contact dermatitis.

CD226 deficiency exacerbated intestinal immune dysregulation in mice with dinitrochlorobenzene-induced atopic dermatitis

Intestinal mucosal immunity plays a pivotal role in host defence. In this study, we found that cluster of differentiation 226 (CD226) gene knockout (KO) led to more severe atopic dermatitis (AD)-related skin pathologies and bowel abnormalities in a 2,4-dinitrochlorobenzene (DNCB)-induced AD-like mouse model. Following DNCB administration, the expression of CD226 was elevated in intestinal mucosal tissues, including group 3 innate lymphoid cells (ILC3s) and CD4⁺ T cells of Peyer's patches (PPs). CD226 deficiency led to an overactive intestinal immune response in the AD-like mice, as evidenced by increased inflammation and Th1/Th2-related cytokine levels as well as increased Paneth cell numbers and antimicrobial peptide (AMP) expression, which was likely due to the higher interleukin (IL)-22 production in the lamina propria. Additionally, CD226 deficiency increased the production of IL-4 and IL-17 in mesenteric lymph nodes as well as the number of PPs and expression of immunoglobulin (Ig) A in B cells. Moreover, insufficient expression of CD226 affected the characterization of intraepithelial and lamina propria lymphocytes in the intestinal mucosa. Finally, the number of PPs was increased in CD4⁺ T cell-specific CD226 KO and regulatory T (Treg) cell-specific CD226 KO mice; thus, loss of CD226 in Treg cells resulted in impaired Treg cell-suppressive function. Therefore, our findings indicate that CD226 deficiency alters intestinal immune functionality in inflammatory diseases.

Does kimchi deserve the status of a probiotic food?

Kimchi is a traditional fermented vegetable side dish in Korea and has become a global health food. Kimchi undergoes spontaneous fermentation, mainly by lactic acid bacteria (LAB) originating from its raw ingredients. Numerous LAB, including the genera Leuconostoc, Weissella, and Lactobacillus, participate in kimchi fermentation, reaching approximately 9-10 log colony forming units per gram or milliliter of food. The several health benefits of LAB (e.g., antioxidant and anti-inflammatory properties) combined with their probiotic potential in complex diseases including obesity, cancer, atopic dermatitis, and immunomodulatory effect have generated an interest in the health effects of LAB present in kimchi. In order to estimate the potential of kimchi as a probiotic food, we comprehensively surveyed the health functionalities of kimchi and kimchi LAB, and their effects on human gut environment, highlighting the probiotics function.

Are Fermented Foods Effective against Inflammatory Diseases?

Fermented foods have been used over the centuries in various parts of the world. These foods are rich in nutrients and are produced naturally using various biological tools like bacteria and fungi. Fermentation of edible foods has been rooted in ancient cultures to keep food for preservation and storage for a long period of time with desired or enhanced nutritional values. Inflammatory diseases like rheumatoid arthritis, osteoarthritis, and chronic inflammatory pain are chronic disorders that are difficult to treat, and current treatments for these disorders fail due to various adverse effects of prescribed medications over a long period of time. Fermented foods containing probiotic bacteria and fungi can enhance the immune system, improve gastrointestinal health, and lower the risk of developing various inflammatory diseases. Foods prepared from vegetables by fermentation, like kimchi, sauerkraut, soy-based foods, or turmeric, lack proper clinical and translational experimental studies. The current review has focused on the effectiveness of various fermented foods or drinks used over centuries against inflammation, arthritis, and oxidative stress. We also described potential limitations on the efficacies or usages of these fermented products to provide an overarching picture of the research field.

Mesenchymal Stem Cells and Their Exocytotic Vesicles

Mesenchymal stem cells (MSCs), as a kind of pluripotent stem cells, have attracted much attention in orthopedic diseases, geriatric diseases, metabolic diseases, and sports functions due to their osteogenic potential, chondrogenic differentiation ability, and adipocyte differentiation. Anti-inflammation, anti-fibrosis, angiogenesis promotion, neurogenesis, immune regulation, and secreted growth factors, proteases, hormones, cytokines, and chemokines of MSCs have been widely studied in liver and kidney diseases, cardiovascular and cerebrovascular diseases. In recent years, many studies have shown that the extracellular vesicles of MSCs have similar functions to MSCs transplantation in all the above aspects. Here we review the research progress of MSCs and their exocrine vesicles in recent years.

Stabilization of Acne Vulgaris-Associated Microbial Dysbiosis with 2% Supramolecular Salicylic Acid

Facial microbiota dysbiosis is an important factor in causing acne vulgaris. The present study aimed to analyze the effect of 2% Supramolecular Salicylic Acid (SSA) on acne-associated facial bacteria. In the current study, 30 acne vulgaris patients (treated with 2% SSA for eight weeks) and ten volunteers with no facial acne were selected. Samples from acne patients (before and after treatment) and volunteers (not treated) were analyzed via high throughput sequencing, Deblur algorithm, and R microbiome package. After treatment with 2% SSA, the total lesion count and global acne grading system (GAGS) score reduced significantly (p < 0.001). Metagenomic sequencing analysis revealed that the pre-treated acne group had low α and deviated β diversity compared to the control and post-treated acne groups. Due to the treatment with 2% SSA, α diversity index was increased and β diversity was stabilized significantly (p < 0.001). The relative abundance of bacterial genera in the pre-treated acne group was uneven and had a high proportion of Staphylococcus, Ralstonia, and Streptococcus. The proportion of these three genera was significantly decreased in the post-treated group, and overall bacteria genera distribution tends toward the healthy individual. It is concluded that 2% SSA normalizes the microbial communities associated with the skin.

Lactobacillus for the treatment and prevention of atopic dermatitis: Clinical and experimental evidence

Atopic dermatitis (AD) is a chronic inflammatory skin disease, accompanied by itching and swelling. The main pathological mechanism of AD is related to the imbalance between Type 2 helper cells (Th2 cells) and Type 1 helper cells (Th1 cells). Currently, no safe and effective means to treat and prevent AD are available; moreover, some treatments have side effects. Probiotics, such as some strains of Lactobacillus, can address these concerns via various pathways: i) facilitating high patient compliance; ii) regulating Th1/Th2 balance, increasing IL-10 secretion, and reducing inflammatory cytokines; iii) accelerating the maturation of the immune system, maintaining intestinal homeostasis, and improving gut microbiota; and iv) improving the symptoms of AD. This review describes the treatment and prevention of AD using 13 species of Lactobacillus. AD is commonly observed in children. Therefore, the review includes a higher proportion of studies on AD in children and fewer in adolescents and adults. However, there are also some strains that do not improve the symptoms of AD and even worsen allergies in children. In addition, a subset of the genus Lactobacillus that can prevent and relieve AD has been identified in vitro. Therefore, future studies should include more in vivo studies and randomized controlled clinical trials. Given the advantages and disadvantages mentioned above, further research in this area is urgently required.

The causality between intestinal flora and allergic diseases: Insights from a bi-directional two-sample Mendelian randomization analysis

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 methods

We 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.

Results

A 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.

Inhibitory effects of antibiotic-induced gut microbiota depletion on acute itch behavior in mice

BACKGROUND

The gut microbiota is known to be associated with the regulation of many neurological diseases and behaviors, including chronic pain. However, it is unclear whether the gut microbiota is critical to the itch sensation. In this study, we investigated the effects of gut microbiota depletion on acute itch.

METHODS

First, an antibiotic cocktail was orally administered to deplete the gut microbiota in male C57BL/6 mice. Then, pruritogens were intradermally injected to induce acute itch behavior. In addition, antibiotic-treated mice received transplantation of fecal microbiota from untreated mice, followed by tests for acute itch. The changes in c-Fos expression in trigeminal ganglia (TG) neurons were also investigated by immunofluorescence staining.

RESULTS

Our results indicated that chronic antibiotic treatment significantly reduced the diversity and richness of the gut microbiota of mice. Compared to vehicle-treated mice, antibiotic-treated mice showed reductions in acute itch behavior induced by compound 48/80, chloroquine (CQ), and serotonin (5-HT), respectively. Moreover, repositioning of microbiota reversed the reductions in acute itch behavior in antibiotic-treated mice. In addition, immunofluorescence staining revealed that antibiotic-treated mice displayed decreased c-Fos expression in ipsilateral TG compared to controls.

CONCLUSIONS

Our study, for the first time, discovered that antibiotic-induced gut microbiota depletion could reduce acute itch behavior, which may be connected with decreased TG neuronal activity.

Tremella fuciformis polysaccharides alleviate induced atopic dermatitis in mice by regulating immune response and gut microbiota

Atopic dermatitis (AD), characterized by severe pruritus, immune imbalance, and skin barrier dysfunction, has a high incidence worldwide. Recent evidence has shown that the modulation of gut microbiota is crucial for alleviating clinical symptoms of AD. Tremella fuciformis polysaccharides (TFPS) have been demonstrated to have a variety of biological activities such as immunomodulatory, anti-tumor, antioxidant, anti-inflammatory, neuroprotective, hypoglycemic and hypolipidemic effects. However, their effects on AD treatment have never been investigated. In this study, we compared the therapeutic effects of topical or oral administration of TFPS on AD in dinitrofluorobenzene (DNFB)-induced AD mice. Both topical application and oral administration of TFPS led to improvement on transdermal water loss, epidermal thickening, and ear edema in AD mice, but the oral administration showed significantly better efficacy than the topical application. The TFPS treatment increased the proportion of CD4 (+) CD25 (+) Foxp3 (+) regulatory T cells in mesenteric lymph nodes. Additionally, the non-targeted metabolomics and sequencing of 16S rDNA amplicons were performed, revealing metabolite modulation in feces and changed composition of gut microbiota in mice, which were induced for AD-like disorder and treated by oral administration of TFPS. Collectively, these data suggest that the oral administration of TFPS may constitute a novel effective therapy for AD, with underlying mechanisms associated with the regulation of immune response, and improvement of both metabolism and the composition of intestinal microbiota.

Latilactobacillus sakei: a candidate probiotic with a key role in food fermentations and health promotion

Latilactobacillus sakei is used extensively in industrial production and food fermentations. The species is primarily derived from fermented meat and vegetable products and is also found in human feces. Genomics and metabolomics have revealed unique metabolic pathways in L. sakei and molecular mechanisms underlying its competitive advantages in different habitats, which are mostly attributed to its flexible carbohydrate metabolism, cold tolerance, acid and salt tolerance, ability to cope with oxygen changes, and heme uptake. In recent years, probiotic effects of L. sakei and its metabolites have been identified, including the ability to effectively alleviate metabolic syndrome, inflammatory bowel disease, and atopic dermatitis. This review summarizes the genomic and metabolic characteristics of L. sakei and its metabolites and describes their applications, laying a foundation for their expanded use across the food and healthcare industries.

The intestinal microbiome and the role of probiotics/prebiotics in the therapeutic approach of atopic dermatitis: A review

Atopic dermatitis (AD) is the most common chronic inflammatory skin condition, characterized by multiple recurrent eczematous lesions and intense itchiness. It is a multifactorial skin disorder involving an association between genetic and environmental factors that lead to a defect of the epithelial barrier in conjunction with immunological dysregulation. Over the last decade, there has been an increasing understanding of the role of the human microbiota in preserving skin integrity and that a shift in the homeostasis of these microorganisms may lead to dysbiosis and disease. Diversity in the intestinal microbiome and its role in the etiopathogenesis of AD has been described and has become of great interest. In this report, we have reviewed the importance of the gut microbiome and the possible mechanism in the pathogenesis of AD as well as the therapeutic impact of probiotics and prebiotics

Limosilactobacillus reuteri Attenuates Atopic Dermatitis via Changes in Gut Bacteria and Indole Derivatives from Tryptophan Metabolism

Gut bacteria are closely associated with the development of atopic dermatitis (AD) due to their immunoregulatory function. Indole derivatives, produced by gut bacteria metabolizing tryptophan, are ligands to activate the aryl hydrocarbon receptor (AHR), which plays a critical role in attenuating AD symptoms. Limosilactobacillus reuteri, a producer of indole derivatives, regulates mucosal immunity via activating the AHR signaling pathway. However, the effective substance and mechanism of L. reuteri in the amelioration of AD remain to be elucidated. In this research, we found that L. reuteri DYNDL22M62 significantly improved AD-like symptoms in mice by suppressing IgE levels and the expressions of thymic stromal lymphopoietin (TSLP), IL-4, and IL-5. L. reuteri DYNDL22M62 induced an increase in the production of indole lactic acid (ILA) and indole propionic acid (IPA) via targeted tryptophan metabolic analysis and the expression of AHR in mice. Furthermore, L. reuteri DYNDL22M62 increased the proportions of Romboutsia and Ruminococcaceae NK4A214 group, which were positively related to ILA, but decreased Dubosiella, which was negatively related to IPA. Collectively, L. reuteri DYNDL22M62 with the role of modulating gut bacteria and the production of indole derivatives may attenuate AD via activating AHR in mice.

Skin microbiome reconstruction and lipid metabolism profile alteration reveal the treatment mechanism of Cryptotanshinone in the acne rat

BACKGROUND

Acne has become one of the most prevalent skin disorders, affecting mostly young people's physical and mental health globally. Cryptotanshinone (CPT) is a potential drug for acne, but its mechanism of acne treatment has not been thoroughly studied on the microbiota. Till date, only a few studies are directed to the impact of acne therapy on skin microbiota and lipid metabolites.

PURPOSE

The action mechanism of CPT treatment of acne was investigated by the strategy of microbiome integration with lipidomics.

METHODS

The 16Sr DNA sequencing was used to detect skin microbiota composition, and absolute quantitative lipidomics was utilized to identify lipid metabolites profiles levels. Four key proteins of the glycolysis pathway were detected with the immunochemistry method. Antibacterial analysis was used to evaluate CPT treatment of acne.

RESULTS

CPT significantly inhibited Staphylococcus epidermidis and Staphylococcus aureus. Combination of the skin microbiome and lipidomics analysis, 29 types of differentially expressed flora (DEFs) and 782 differentially expressed lipid metabolites (DELMs) were significantly altered, especially Staphylococcus, Corynebacterium, Ralstonia, Enhydrobacter, Burkholderia, and Streptococcus. Cer was mainly regulated by Staphylococcus and Corynebacterium, whereas TG and DG were mainly regulated by Ralstonia, Enhydrobacter, Burkholderia, and Streptococcus. The glycolysis pathway was significantly regulated by Staphylococcus on CPT treatment of acne. The energy metabolism, lipid metabolism, immune system, glycan biosynthesis, and metabolism could be reversed by CPT.

CONCLUSION

CPT might help acne rats rebuild their skin microbiota and alter lipid metabolism signatures. Furthermore, since skin microbes and skin lipid metabolites have a close correlation and are both regulated by CPT, the findings potentially provide a research foundation for the discovery of biomarkers of skin microbiome imbalance and targeted treatment of acne development mechanisms.

D-galactose Intake Alleviates Atopic Dermatitis in Mice by Modulating Intestinal Microbiota

Atopic dermatitis (AD) is one of the most prevalent, chronic and persistent inflammatory skin diseases closely associated with intestinal microbiota. To evaluate the effect of D-galactose intake on AD, we orally administered D-galactose to BALB/c mice whose ears and skin were treated with 2,4-dinitrochlorobenzene (DNCB). D-galactose alleviated DNCB-induced AD-like phenotypes such as redness, scaling/dryness and excoriation. Ear thickness was also decreased by D-galactose administration. Histopathological analysis revealed decreased epidermal thickening, infiltration of immune cells, especially mast cells, in the dermis. Total levels of serum IgE representing the immunological response of AD were decreased by D-galactose administration. Microbiota analysis showed that D-galactose administration restored gut microbiota profiles, which were altered in AD mice, characterized by increased abundance of Bacteroidetes and decreased abundance of Firmicutes. The increased abundance of Bacteroides and the decreased abundance of Prevotella and Ruminococcus were reversed by D-galactose treatment, following improvement of AD. Our results suggest the possible use of D-galactose as a prebiotic to alleviate AD by altering gut microbiota.

Lactobacillus: Friend or Foe for Systemic Lupus Erythematosus?

The cause of Systemic Lupus Erythematosus (SLE) remains largely unknown, despite the fact that it is well understood that a complex interaction between genes and environment is required for disease development. Microbiota serve as activators and are essential to immune homeostasis. Lactobacillus is thought to be an environmental agent affecting the development of SLE. However, beneficial therapeutic and anti-inflammatory effects of Lactobacillus on SLE were also explored. The discovery of Lactobacillus involvement in SLE will shed light on how SLE develops, as well as finding microbiota-targeted biomarkers and novel therapies. In this review, we attempt to describe the two sides of Lactobacillus in the occurrence, development, treatment and prognosis of SLE. We also discuss the effect of different strains Lactobacillus on immune cells, murine lupus, and patients. Finally, we try to illustrate the potential immunological mechanisms of Lactobacillus on SLE and provide evidence for further microbiota-targeted therapies.

Bifidobacterium longum mediated tryptophan metabolism to improve atopic dermatitis via the gut-skin axis

Gut microbial disturbance affects allergic diseases including asthma, atopic dermatitis (AD) via the aberrant immune response. Some Bifidobacterial species and strains have been reported to improve AD via modulating immune-microbe interactions in patients. However, the effective metabolites and mechanism of alleviating AD in bifidobacteria remain to be elucidated. This study aimed to explore the microbial metabolite and mechanism of Bifidobacterium longum to improve AD. Based on shotgun metagenomic sequencing and UHPLC Q-Exactive-MS targeted metabolic experiments in vitro and in vivo, we focused on tryptophan metabolism and indole derivatives, which are endogenous ligands for aryl hydrocarbon receptor (AHR). Indole-3-carbaldehyde (I3C), a tryptophan metabolite of B. longum CCFM1029 activated AHR-mediated immune signaling pathway to improve AD symptoms in animal and clinical experiments. B. longum CCFM1029 upregulated tryptophan metabolism and increased I3C to suppress aberrant T helper 2 type immune responses, but these benefits were eliminated by AHR antagonist CH223191. Furthermore, B. longum CCFM1029 reshaped gut microbial composition in AD patients, increased fecal and serum I3C, and maintained the abundance of Lachnospiraceae related to tryptophan metabolism of gut microbiota. The results suggested that based on the interactions of the gut-skin axis, B. longum CCFM1029 upregulated tryptophan metabolism and produced I3C to activate AHR-mediated immune response, alleviating AD symptoms. Indole derivates, microbial metabolites of tryptophan, may be the potential metabolites of bifidobacteria to alleviate AD via the AHR signaling pathway.

Fermented Food in Asthma and Respiratory Allergies—Chance or Failure?

In the last few decades, a dramatic increase in the global prevalence of allergic diseases and asthma was observed. It was hypothesized that diet may be an important immunomodulatory factor influencing susceptibility to allergic diseases. Fermented food, a natural source of living microorganisms and bioactive compounds, has been demonstrated to possess health-promoting potentials and seems to be a promising strategy to reduce the risk of various immune-related diseases, such as allergic diseases and asthma. The exact mechanisms by which allergic diseases and asthma can be alleviated or prevented by fermented food are not well understood; however, its potential to exert an effect through modulating the immune response and influencing the gut microbiota has been recently studied. In this review, we provide the current knowledge on the role of diet, including fermented foods, in preventing or treating allergic diseases and asthma.

Skin Microbiota in Atopic Dermatitis

The skin microbiota represents an ecosystem composed of numerous microbial species interacting with each other, as well as with host epithelial and immune cells. The microbiota provides health benefits to the host by supporting essential functions of the skin and inhibiting colonization with pathogens. However, the disturbance of the microbial balance can result in dysbiosis and promote skin diseases, such as atopic dermatitis (AD). This review provides a current overview of the skin microbiota involvement in AD and its complex interplay with host immune response mechanisms, as well as novel therapeutic strategies for treating AD focused on restoring skin microbial homeostasis.

Oxidative Stress and Gut Microbiome in Inflammatory Skin Diseases

Oxidative stress plays a dominant role in inflammatory skin diseases. Emerging evidence has shown that the close interaction occurred between oxidative stress and the gut microbiome. Overall, in this review, we have summarized the impact of oxidative stress and gut microbiome during the progression and treatment for inflammatory skin diseases, the interactions between gut dysbiosis and redox imbalance, and discussed the potential possible role of oxidative stress in the gut-skin axis. In addition, we have also elucidated the promising gut microbiome/redox-targeted therapeutic strategies for inflammatory skin diseases.

Ruminococcus gnavus ameliorates atopic dermatitis by enhancing Treg cell and metabolites in BALB/c mice

BACKGROUND

Ruminococcus gnavus (R. gnavus) are mucin-degrading gut bacteria that play a key role in the early colonization of the gut by serving as endogenous sources of nutrients. They can also influence immune development. We had previously reported a lower abundance of R. gnavus in infants with atopic dermatitis (AD) compared with that in healthy subjects. However, the underlying mechanisms remain unclear. In this study, we investigated the effect of orally administered R. gnavus on antibiotic treatment-induced gut dysbiosis (and the underlying mechanism) in a mouse model of AD.

METHODS

Four-week-old female BALB/C mice were administered antibiotic cocktails for 2 weeks. R. gnavus was orally administered throughout the study duration. At 6 weeks of age, AD was induced by epidermal sensitization with ovalbumin. AD phenotypes and systemic and gut immune responses were investigated.

RESULTS

Orally administered R. gnavus significantly reduced AD-associated parameters (i.e., transepidermal water loss, clinical score, total serum immunoglobulin (Ig) E level, OVA-specific IgE level, and skin inflammation). R. gnavus treatment also resulted in significant downregulation of T helper 2-related cytokine mRNA and upregulation of interleukin (IL)-10 and Foxp3 in the skin. The population of CD4⁺ FOXP3⁺ T cells in mesenteric- and skin-draining lymph nodes and butyrate levels in the cecum increased in R. gnavus-administered AD mice.

CONCLUSIONS

Immune modulation by orally administered R. gnavus may alleviate AD symptoms through the enhancement of regulatory T-cell counts and short-chain fatty acids production in AD mice.

Composition and Diversity of the Ocular Surface Microbiota in Patients With Blepharitis in Northwestern China

Purpose: To investigate the composition and diversity of the microbiota on the ocular surface of patients with blepharitis in northwestern China via 16S rDNA amplicon sequencing.

Methods: Thirty-seven patients with blepharitis divided into groups of anterior, posterior and mixed blepharitis and twenty healthy controls from northwestern China were enrolled in the study. Samples were collected from the eyelid margin and conjunctival sac of each participant. The V3–V4 region of bacterial 16S rDNA in each sample was amplified and sequenced on the Illumina HiSeq 2500 sequencing platform, and the differences in taxonomy and diversity among different groups were compared.

Results: The composition of the ocular surface microbiota of patients with blepharitis was similar to that of healthy subjects, but there were differences in the relative abundance of each bacterium. At the phylum level, the abundances of Actinobacteria, Cyanobacteria, Verrucomicrobia, Acidobacteria, Chloroflexi, and Atribacteria were significantly higher in the blepharitis group than in the healthy control group, while the relative abundance of Firmicutes was significantly lower (p < 0.05, Mann-Whitney U). At the genus level, the abundances of Lactobacillus, Ralstonia, Bacteroides, Akkermansia, Bifidobacterium, Escherichia-Shigella, Faecalibacterium, and Brevibacterium were significantly higher in the blepharitis group than in the healthy control group, while the relative abundances of Bacillus, Staphylococcus, Streptococcus, and Acinetobacter were significantly lower in the blepharitis group (p < 0.05, Mann-Whitney U). The microbiota of anterior blepharitis was similar to that of mixed blepharitis but different from that of posterior blepharitis. Lactobacillus and Bifidobacterium are biomarkers of posterior blepharitis, and Ralstonia is a biomarker of mixed blepharitis. There was no significant difference in the ocular surface microbiota between the eyelid margin and conjunctival sac with or without blepharitis.

Conclusion: The ocular surface microbiota of patients with blepharitis varied among different study groups, according to 16S rDNA amplicon sequencing analysis. The reason might be due to the participants being from different environments and having different lifestyles. Lactobacillus, Bifidobacterium, Akkermansia, Ralstonia, and Bacteroides may play important roles in the pathogenesis of blepharitis.

A New Formulation of Probiotics Attenuates Calcipotriol-Induced Dermatitis by Inducing Regulatory Dendritic Cells

Atopic dermatitis (AD) is a recurrent chronic inflammatory skin disease affecting up to 30% of the children population, and immuno-regulatory therapy that could modify the course of disease is urgently needed. Probiotics have demonstrated therapeutic effects on AD and could potentially regulate the disease process. However, the efficacy of probiotics for AD is inconsistent among different studies, which is mainly due to the elusive mechanism and different species and (or) strains used. In this study, we designed a mixture of five strains of probiotics (named IW5) and analyzed the effect and mechanism of IW5 on calcipotriol (MC903)-induced AD-like dermatitis. We found that IW5 significantly alleviated skin inflammation of the MC903-induced AD in mice. Administration with IW5 induced increased production of regulatory T cells and regulatory dendritic cells (DCregs) in the mesenteric lymph nodes. We also found that the diversity of the gut microbiota in the mice with MC903-induced dermatitis was increased after IW5 administration, and the level of butyrate in the gut was elevated. In cell culture, butyrate induced the production of DCregs. Our study revealed the therapeutic effects of a newly designed probiotics mixture and uncovered a possible mechanism, providing a foundation for future clinical studies.

Latilactobacillus sakei WIKIM31 Decelerates Weight Gain in High-Fat Diet-Induced Obese Mice by Modulating Lipid Metabolism and Suppressing Inflammation

Obesity and related metabolic diseases are major problems worldwide. Some probiotics are currently considered potential therapeutic strategies for obesity. We aimed to investigate the antiobesity efficacy of Latilactobacillus sakei WIKIM31 in obese mice induced by a high fat diet. The administration of a high-fat diet with L. sakei WIKIM31 reduced body weight gain, epididymal fat mass, triglyceride and total cholesterol levels in the blood, and remarkably decreased the expression of lipogenesis-related genes in the epididymal adipose tissue and liver. Interestingly, intake of L. sakei WIKIM31 improved gut barrier function by increasing the gene expression of tight junction proteins and suppressing the inflammatory responses. Additionally, L. sakei WIKIM31 enhanced the production of short-chain fatty acids, such as butyrate and propionate, in the intestinal tract. These results showed that L. sakei WIKIM31 can be used as a potential therapeutic probiotic for obesity.

Prevention of Atopic Dermatitis in Mice by Lactobacillus Reuteri Fn041 Through Induction of Regulatory T Cells and Modulation of the Gut Microbiota

SCOPE

The development of atopic dermatitis (AD) in infants is closely related to the lagging development of intestinal microbiota, including that inoculated by breast milk bacteria, and immune development. Lactobacillus reuteri Fn041 is a secretory immunoglobulin A (sIgA) -coated bacterium derived from human milk.

METHODS AND RESULTS

We intervened with L. reuteri Fn041 in maternal and offspring BALB/C mice during late gestation and lactation and after weaning of the pups, respectively. AD was then induced with MC903. L. reuteri Fn041 significantly suppressed AD symptoms such as skin swelling, mast cell and eosinophil infiltration. This effect was attributed to the regulation of the systemic Th1 and Th2 cytokine ratios and the promotion of CD4⁺ CD25⁺ Foxp3⁺ regulatory T cell proliferation in mesenteric lymph nodes. It is also associated with the regulation of intestinal microbiota, particularly promoting Lactobacillus and Akkermansia.

CONCLUSIONS

Our study strengthens the understanding that breast milk-derived sIgA coated potential probiotics are involved in the development of infant intestinal microbiota, thus promoting immune development and preventing allergic diseases, and expanding the knowledge of breast milk sIgA and bacterial interactions on infant immune development. This article is protected by copyright. All rights reserved.

Implications of Gut Microbiota in Complex Human Diseases

Humans, throughout the life cycle, from birth to death, are accompanied by the presence of gut microbes. Environmental factors, lifestyle, age and other factors can affect the balance of intestinal microbiota and their impact on human health. A large amount of data show that dietary, prebiotics, antibiotics can regulate various diseases through gut microbes. In this review, we focus on the role of gut microbes in the development of metabolic, gastrointestinal, neurological, immune diseases and, cancer. We also discuss the interaction between gut microbes and the host with respect to their beneficial and harmful effects, including their metabolites, microbial enzymes, small molecules and inflammatory molecules. More specifically, we evaluate the potential ability of gut microbes to cure diseases through Fecal Microbial Transplantation (FMT), which is expected to become a new type of clinical strategy for the treatment of various diseases.