Search Results (507)

Atopic dermatitis (AD) is a chronic inflammatory skin disorder associated with immune dysregulation, skin barrier dysfunction, and microbial dysbiosis characterized by Staphylococcus aureus overcolonization and reduced bacterial diversity. Beyond its classical role in calcium homeostasis, Vitamin D (VD) influences skin immunity and microbial composition. This review summarizes current knowledge on VD metabolism, its immunological pathways in AD, and its interactions with the skin microbiome. Recent evidence positions the skin as an active immunological organ rather than a passive barrier. Commensal bacteria such as Staphylococcus epidermidis not only inhibit pathogens by producing bacteriocins and modulins but also generate ceramides and short-chain fatty acids (SCFAs) that stabilize the lipid barrier. Moreover, dermal fibroblasts and preadipocytes produce antimicrobial peptides, while resident γδ T cells release growth factors like fibroblast growth factor 7 (FGF7), linking host defense with tissue regeneration. VD modulates AD by suppressing T helper 2 cells/T helper 17 cell responses, enhancing regulatory T cell development, inducing antimicrobial peptides, and strengthening skin and gut barrier integrity. Its interaction with the microbiome and pathways such as SCFA and aryl hydrocarbon receptor (AhR) signaling supports its potential as an adjunctive therapy in AD management. Evidence from mechanistic studies and animal models suggests that VD supplementation may modulate inflammation and microbial diversity. Clinical implications, therapeutic perspectives, and future research directions highlight the potential of VD as a therapeutic adjunct in AD management. Full article

The host microbiome is a promising source of probiotics for aquaculture species including Nile tilapia. In this study, the probiotic potential of autochthonous bacterial isolates from Nile tilapia and carp mid-intestines were screened in vitro. Two isolates (C61 and T70), closely related to Bacillus subtilis, exhibited antagonistic activity against multiple pathogen species and demonstrated multiple digestive enzyme activities. Their antagonistic activity in Aeromonas hydrophila assays remained even under simulated intestinal juice (SIJ) exposure. Subsequently, C61 (PT1) and T70 (PT2) were added to experimental diets at log 7 CFU/g of diet, and fed to Nile tilapia (5.32 ± 0.12 g) for 40 days. There were no significant differences observed in the growth performance across treatments. Despite limited Bacillus intestinal recovery levels, 16S rRNA gene metabarcoding revealed subtle shifts in the intestinal microbial community composition of the probiotic-fed groups. In addition, the PT1 group showed significantly longer mucosal fold length, elevated intestinal and skin goblet cell levels, and higher skin goblet cell coverage compared to the control. These results indicate the potential benefits of the isolates as functional feed additives for enhancing the mucosal health of Nile tilapia, but their benefits were likely achieved through transient activity given the low level of Bacillus recovery in the intestine. Full article

The human skin microbiome, defined as a multifaceted ecosystem comprising bacteria, fungi, viruses, and mites, plays a pivotal role in maintaining skin homeostasis and regulating immune responses. In recent years, an increasing amount of evidence has illuminated the considerable influence exerted by microbiomes on the pathophysiology of dermatological ailments. This review provides a comprehensive synthesis of contemporary findings concerning the microbiome’s role in acne, aging, hyperpigmentation, and hair disorders, while also addressing the emerging concept of the gut–skin axis and how it could interfere in these skin disorders. Alterations in microbial composition, referred to as dysbiosis, have been associated with inflammatory processes and barrier dysfunction, thereby contributing to the severity and chronicity of diseases. Distinct microbial profiles have been identified as correlating with specific skin conditions. For instance, variations in Cutibacterium acnes phylotypes have been associated with the development of acne, whereas alterations in Corynebacterium and Staphylococcus species have been linked to the processes of aging and pigmentation patterns. Furthermore, the composition of the microbiome is examined in relation to its impact on cosmetic outcomes. It also engages with increasing interest in the modulation of microbiota through the topical application of bioactive compounds. The incorporation of prebiotics, probiotics, and postbiotics into cosmetic formulations constitutes a novel strategy aimed at enhancing skin health. In the domain of dermatological therapies, postbiotics have emerged as a significant class of substances, particularly due to their remarkable stability, safety, and immunomodulatory properties. These characteristics position them as promising candidates for incorporation into dermatological treatments. Recent studies have underscored the significance of microbiome-informed strategies within the domains of therapeutic and preventive dermatology, emphasizing the potential of such approaches to positively influence patient outcomes. As our understanding of this field continues to evolve, skin microbiomes are poised to emerge as a pivotal area of focus in the realm of personalized skin care and treatment. This development presents novel and innovative approaches for the management of skin conditions, characterized by enhanced specificity and efficacy. Full article

Maintaining the balance between the host and commensal microorganisms is essential for skin health. The disruption of this equilibrium (dysbiosis) can contribute to inflammatory and infectious diseases and accelerate skin aging. Dysbiosis also accompanies skin cancers and may influence their progression. Causes of dysbiosis include exogenous factors such as cosmetics, UV radiation, pollution, and diet, as well as endogenous factors like stress, hormonal imbalances, and aging. Standard antibacterial treatments often eliminate beneficial microbes and may exacerbate conditions. Consequently, there is growing interest in alternative strategies—notably natural plant- and animal-derived products—that can modulate the skin microbiome more selectively and gently. This review presents current knowledge on skin microbiome physiology and dysbiosis and discusses natural compounds and microbiome-based therapies (probiotics, prebiotics, postbiotics) that modulate the skin microbiota. Unlike prior reviews, we provide a comparative perspective on emerging compound classes (e.g., peptides, lipids) and integrate the skin–gut axis concept into the framework, highlighting mechanistic insights at molecular and clinical levels. Our synthesis emphasizes distinct modes of action and evidence levels—from in vitro mechanisms to clinical outcomes—and offers guidance for formulation of microbiome-compatible products. Full article

Atopic dermatitis (AD) is a chronic inflammatory skin disease marked by pruritus and eczematous lesions that significantly impacts patient quality of life. This review covers the intricate interplay of barrier dysfunction, immune dysregulation, and microbial dysbiosis in the complex pathophysiology of AD. The roles of epigenetic factors and environmental exposures are also examined. The evolving understanding of these factors has revolutionized AD treatment. Beyond foundational topical agents, the landscape for moderate-to-severe AD treatment is now dominated by highly targeted immunotherapies, such as biologics and Janus Kinase (JAK) inhibitors, that precisely block specific inflammatory pathways. Emerging strategies explore microbiome modulation and vitamin D supplementation. This paradigm shift from broad immunosuppression to precision medicine offers improved disease control and reduced systemic toxicities and enables more personalized AD management, significantly benefiting patients. Full article

Plant-derived extracellular vesicles (PDEVs) are rapidly gaining popularity in cosmetics and regenerative medicine due to their biocompatibility, natural origin and promising bioactive properties. Nevertheless, the absence of standardized guidelines for their characterization has resulted in an inconsistent, unregulated landscape. This compromises product reproducibility, consumer safety, and scientific credibility. Here, a comprehensive set of minimal characterization guidelines for PDEVs is proposed to include physical and chemical profiling, molecular marker identification, cargo analysis, and stability assessment under storage and formulation conditions. Functional validation through cellular uptake assays, activity tests, and advanced in vitro or ex vivo models that replicate realistic skin exposure scenarios is pivotal. Requirements for transparent labelling, reproducible sourcing, batch-to-batch consistency, and biological activity substantiation to support claims related to skin regeneration, anti-aging, and microbiome modulation are also required. By establishing a harmonized baseline for quality and efficacy evaluation, these guidelines aim to elevate the scientific standards and promote the safe, ethical, and effective use of PDEV-based ingredients in cosmetic and biomedical applications. Full article

The lymphocystis disease virus (LCDV) is a widespread disease in Mediterranean aquaculture and could lead to losses in fry as well as prevent the sale of adult gilthead seabream (Sparus aurata), affecting both hatchery and on-growing stages. Although LCDV infections are often considered self-limiting, they can lead to severe outcomes due to skin microbiome alterations that promote secondary infections, while also reducing growth and marketability, causing substantial economic losses. Basic biosecurity measures are not successful, and there is no available commercial vaccine. This study evaluated diets supplemented with Origanum vulgare and Cinnamomum zeylanicum essential oils (1% and 2%) in gilthead seabream experimentally infected with LCDV. Preventive feeding (90 days before infection) and therapeutic feeding (initiated at infection) were compared across 11 experimental groups, including infected, recovered, and control groups. Results showed that essential oils were more effective prophylactically than therapeutically, highlighting their protective role when incorporated into diets. Cinnamon-supplemented groups consistently exhibited lower prevalence and mortality than oregano groups. High DNA damage values linked to reduced mortality, particularly in the CIN90.1 group, demonstrated that viral dissemination was most restricted. In conclusion, essential oils modulated LCD progression by influencing viral interactions with DNA damage repair mechanisms, supporting their potential for disease control in intensive aquaculture. Full article

The synergistic effects of stratospheric ozone depletion and climate change are intensifying surface ultraviolet-B (UVB) radiation, posing a severe threat to amphibians—one of the most endangered vertebrate groups globally. Xenopus laevis, with its cutaneous respiration and limited photoprotective mechanisms, exhibits high sensitivity to UVB, making it a suitable model for ecotoxicological studies. While UVB is known to cause DNA damage, immune suppression, and microbial dysbiosis, its mechanisms in multi-organ interactions, dose–response thresholds, and host–microbiome regulatory networks remain poorly understood. This study employed a gradient UVB exposure regime integrated with histopathology, oxidative stress assays, and 16S rRNA sequencing to systematically evaluate the effects of UVB on (1) cascade damage across skin, liver, and intestinal barriers; (2) immune cell distribution; (3) redox dynamics; and (4) microbial community structure and function. Our findings demonstrate that low-dose UVB activated compensatory antioxidant defenses without structural disruption, whereas exposure beyond a critical threshold induced nonlinear redox collapse, microbial dysbiosis, and multi-organ barrier failure, collectively exacerbating ecological adaptation risks. These results reveal a cross-scale mechanism by which UVB impairs amphibian health via disruption of host–microbe homeostasis, providing a conceptual and empirical framework for assessing species vulnerability under ongoing climate change. Full article

Ichthyophthirius multifiliis poses a significant threat to global aquaculture, yet some fish species exhibit remarkable resistance. This study employed a combined LC-MS-based metabolomics and 16S rRNA gene sequencing approach to investigate the intrinsic mechanisms underlying the differential susceptibility of Percocypris pingi, crucian carp, and yellow catfish. Our results revealed distinct skin molecular and microbial profiles in P. pingi associated with its enhanced resilience. Metabolomic analysis identified a significant upregulation of key antioxidants (L-Glutathione reduced, L-Glutathione oxidized, L-Cysteine-glutathione gisulfide, Uric acid, Histamine, N-Acetylhistamine, and scorbic acid) in P. pingi, most notably L-Glutathione reduced, which was 31- and 59-fold higher than in yellow catfish and crucian carp, respectively. Functional enrichment further highlighted the critical role of enhanced antioxidant capacity (centered on glutathione metabolism) and immune/inflammatory responses in the resistance to I. multifiliis of P. pingi. Concurrently, skin microbiome analysis showed that P. pingi hosted a microbial community distinct from the other two species, with significantly higher α-diversity. Notably, P. pingi skin was significantly depleted of the parasitic bacteria Candidatus_Megaira and Candidatus_Midichloria, which were highly abundant in the susceptible species. Furthermore, predicted metagenomic functions indicated that P. pingi’s microbiota was enriched in fundamental metabolic pathways, whereas the microbiota of crucian carp and yellow catfish was skewed towards disease- and immune-related pathways. In conclusion, our findings demonstrate that the superior resistance of P. pingi to I. multifiliis is likely conferred by a synergistic effect of a robust skin antioxidant capacity (primarily driven by glutathione) and a protective skin microbiome that excludes specific parasites. This study provides novel insights into the multi-faceted mechanisms of disease resistance in fish. Full article

Archaea, one of the three domains of life, are increasingly recognized as consistent, though often underappreciated, members of the human microbiome, yet their roles in health and disease remain poorly understood. Unlike bacteria, no archaeal species have been conclusively identified as primary mammalian pathogens, but their widespread presence across diverse body sites suggests potential indirect contributions to host physiology and pathology. Current evidence is synthesized on archaeal diversity and habitat specificity across multiple human-associated sites, encompassing the gastrointestinal, aerodigestive, and urogenital tracts as well as the skin. Methanogens dominate the lower gastrointestinal tract (LGT), where they influence fermentation dynamics and methane production, while members of the class Nitrososphaeria are prevalent on the skin and upper aerodigestive tract (UAT), reflecting ecological specialization. Variability in archaeal composition across niches highlights possible links to disease processes: methanogens have been associated with irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), obesity, and colorectal cancer (CRC); Methanobrevibacter oralis is enriched in periodontal disease; and archaea have been detected in the lungs of cystic fibrosis patients. Although archaea lack canonical bacterial virulence factors, they may contribute indirectly through metabolic cross-feeding, immune modulation, synergy in polymicrobial infections, and alteration of host–microbiome network dynamics. This review explores the emerging concept of the human “archaeome”, evaluates current evidence for archaeal involvement in disease, and highlights emerging technologies, such as bacteria-MERFISH and multi-omics profiling, that enable translational applications including microbiome diagnostics, therapeutic targeting, and microbiome engineering. Full article

The human skin microbiome plays a crucial role in maintaining skin health by acting as a barrier against pathogens and modulating immune regulation. This case study investigates the skin microbiome of two healthy Korean male individuals in their 20s during Antarctic expeditions, focusing on microbial changes, reversion to pre-expedition states, and the influence of environmental and lifestyle factors. Notable microbial alterations were observed, including increases in Pseudomonadota and decreases in Actinomycetota, indicating pronounced microbial shifts in response to harsh environmental factors such as low temperature and humidity. Post-expedition revealed incomplete recovery to pre-expedition states, with Host A showing a higher resilience index, suggesting faster microbial recovery. Correlation analyses revealed associations between microbial changes and environmental factors (e.g., temperature, humidity, atmospheric pressure) as well as lifestyle factors (e.g., sunblock usage, outdoor activities), highlighting complex interactions between host behaviors and microbiome dynamics. Despite the study’s limited sample size, these findings offer insights into the adaptability and resilience of the skin microbiome under extreme environments, with potential implications for health management and skincare strategies during isolated and prolonged expeditions. Full article

Bats are widely recognized as reservoirs of diverse bacterial pathogens with important implications for human health. Recent zoonotic disease outbreaks have intensified interest in bat microbiomes, with high-throughput sequencing increasingly used to assess microbial diversity. In this article, we review literature from the past five years on bacterial species associated with bats and their potential clinical relevance. Using automated searches and manual filtering, we extracted data from 47 peer-reviewed studies. Most research has focused on guano samples, though interest in skin microbiomes is rising, particularly in relation to Pseudogymnoascus destructans, the agent of white-nose syndrome. China leads in the number of publications, followed by the United States, and amplicon sequencing remains the predominant metagenomic method. Across studies, 4700 bacterial species were reported, including several known human pathogens capable of aerosol transmission or opportunistic infections in immunocompromised individuals. Many of these taxa are classified as global priority targets for antimicrobial drug development by the World Health Organization and the U.S. Centers for Disease Control and Prevention. Given the clinical severity of diseases linked to some species, bats should be integrated into epidemiological surveillance systems. However, the lack of standardized reporting practices significantly limits the comparability and utility of bat microbiome data for robust ecological and epidemiological analyses. Full article

The skin acts as a primary barrier against environmental insults and maintains homeostasis. Injury initiates a wound healing cascade of hemostasis, inflammation, proliferation, and remodeling. In chronic wounds, persistent microbial colonization and inflammation disrupt this process, with bacterial virulence factors acting as key drivers. While the microbiome’s role in chronic wounds is recognized, the effects of individual virulence factors on acute repair remain unclear. Therefore, this study investigated the differential effects of virulence factors derived from five skin-associated bacterial species on acute wound healing dynamics. In this context, virulence factors from Pseudomonas aeruginosa, Staphylococcus aureus, Streptococcus pyogenes, Lactobacillus plantarum, and Enterococcus faecalis were tested on HDF-n cell viability and wound closure, with multiplex ELISA used to assess inflammatory mediator secretion and underlying mechanisms. Overall, virulence factors were generally well tolerated across concentrations (0.05–16 µg/mL) and time points (24, 48 h), with cell viability >80%, except for S. aureus, which reduced viability to ~70% at higher concentrations by 48 h. Wound healing responses varied markedly: S. aureus significantly impaired closure in a dose-dependent manner (~10% closure at 16 µg/µL, 48 h), and E. faecalis similarly delayed repair. In contrast, factors from P. aeruginosa, S. pyogenes, and L. plantarum showed neutral or mildly pro-healing effects. Notably, co-treatment with S. pyogenes partially rescued impairment caused by S. aureus and E. faecalis. Collectively, these findings highlight that bacterial virulence factors have variable impacts on acute wound healing. These findings suggest potential therapeutic applications through targeted modulation or combinations of bacterial factors. Full article

The complexity of adverse responses from radiation injury (RI) followed by physical trauma, namely, radiation combined injury (RCI), is unique and more pronounced than either insult alone due to a poor understanding of the integration of these insults at the molecular/cellular/tissue and/or organ levels. It was shown that mice receiving ⁶⁰Co γ-photon RCI with wounding had a lower LD_50/30 than RI alone. This survival synergism was observed in bone marrow and the gastrointestinal system, as evidenced by an increase in γ-H2AX expression in bone marrow cell DNA, loss of circulatory blood cells, elevation of serum cytokine concentration, and activation of nuclear factor-κB/inducible nitric oxide synthase, and an earlier onset of bacterial infection and sepsis after RCI than after RI was detected. Dysbiosis (imbalance of the gut microbiota) was observed. There remains a pressing need for both prophylactic countermeasures and therapeutic remedies to deal with RCI threats. Investigations of how RCI can affect this important network of communication between the gut microbiota and other organs, including the brain, lung, heart, liver, kidney, and skin, could lead to new and critical interventions and prevention strategies. This review provides an update on new RCI animal models, dynamic changes in cytokine expression, dysbiosis, as well as links between the gut microbiome and other organs after RCI. Full article

This study investigated the therapeutic potential of a novel probiotic combination consisting of Lactococcus cremoris subsp. cremoris MP01 and Lacticaseibacillus paracasei subsp. paracasei MP02, collectively referred to as LCP, in the treatment of canine atopic dermatitis (CAD). In a 60-day open-label, single-arm trial involving eight dogs, notable clinical improvements were observed following daily LCP treatment, as evidenced by decreasing trends in Canine Atopic Dermatitis Extent and Severity Index and Pruritus Visual Analogue Scale scores, as well as a significant reduction in serum immunoglobulin E levels (p < 0.05). Microbiome and short-chain fatty acid (SCFA) analyses were subsequently conducted in a representative subset of six dogs to explore the effects of LCP on the fecal and skin microbial ecosystems. Concomitant alterations in gut and skin microbiome were observed, including a significant reduction in abundance of Erysipelotrichaceae (p < 0.05) and non-significant decreasing trends in Romboutsia, Escherichia/Shigella spp., and Shigella flexneri, along with a trend toward increased SCFA production. Functional prediction using PICRUSt suggested potential involvement of immune- and infection-related signaling pathways, including those associated with nucleotide-binding oligomerization domain-like receptors, retinoic acid-inducible gene I-like receptors and Shigellosis, supporting the hypothesis that LCP may exert its effects through modulation of the gut–skin axis. These findings support LCP as a safe and promising adjunct therapy for CAD, offering a novel microbiome-targeted approach targeting both clinical symptoms and underlying dysbiosis. Further investigation is warranted to optimize probiotic formulations and better understand the mechanisms underlying microbiome-mediated immune modulation in canine allergy. Full article