In vitro evaluation of antibacterial activities and anti-inflammatory effects of Bifidobacterium spp. addressing acne vulgaris

Vibriocidal efficacy of Bifidobacterium bifidum and Lactobacillus acidophilus cell-free supernatants encapsulated in chitosan nanoparticles against multi-drug resistant Vibrio cholerae O1 El Tor

BACKGROUND

Cholera is a diarrheal disease recognized for being caused by toxin-producing Vibrio (V.) cholerae. This study aims to assess the vibriocidal and immunomodulatory properties of derived cell-free supernatants (CFSs) of Bifidobacterium (B.) bifidum and Lactobacillus (L.) acidophilus encapsulated in chitosan nanoparticles (CFSb-CsNPs and CFSa-CsNPs) against clinical multi-drug resistance (MDR) isolates of V. cholerae O1 El Tor.

METHODS

We synthesized CFSb-CsNPs and CFSa-CsNPs using the ionic gelation technique. The newly nanostructures were characterized for size, surface zeta potential, morphology, encapsulation efficacy (EE), stability in different pH values and temperatures, release profile, and in vitro cytotoxicity. The antimicrobial and antibiofilm effects of the obtained nanocomposites on clinical MDR isolates (N = 5) of V. cholerae E1 Tor O1 were investigated by microbroth dilution assay and crystal violet staining, respectively. We conducted quantitative real-time PCR (qRT-PCR) to analyze the relative gene expressions of Bap, Rbmc, CTXAB, and TCP in response to CFSb-CsNPs and CFSa-CsNPs. Additionally, the immunomodulatory effects of formulated structures on the expression of TLR2 and TLR4 genes in human colorectal adenocarcinoma cells (Caco-2) were studied.

RESULTS

Nano-characterization analyses indicated that CFSb-CsNPs and CFSa-CsNPs exhibit spherical shapes under scanning electron microscopy (SEM) imaging, with mean diameters of 98.16 ± 0.763 nm and 83.90 ± 0.854 nm, respectively. Both types of nanoparticles possess positive surface charges. The EE% of CFSb-CsNPs was 77 ± 4.28%, whereas that of CFSa-CsNPs was 62.5 ± 7.33%. Chitosan (Cs) encapsulation leads to increased stability of CFSs in simulated pH conditions of the gastrointestinal tract in which the release rates for CFSb-CsNPs and CFSa-CsNPs were reached at 58.00 ± 1.24% and 55.01 ± 1.73%, respectively at pH = 7.4. The synergistic vibriocidal effects observed from the co-administration of both CFSb-CsNPs and CFSa-CsNPs, as evidenced by a fractional inhibitory concentration (FIC) index of 0.57, resulting in a significantly lower MIC of 2.5 ± 0.05 mg/mL (p < 0.0001) compare to individual administration. The combined antibacterial effect of CFSb-CsNPs and CFSa-CsNPs on Bap (0.14 ± 0.05), Rbmc (0.24 ± 0.01), CTXAB (0.30 ± 0.09), and TCP (0.38 ± 0.01) gene expression was significant (p < 0.001). Furthermore, co-administration of CFSb-CsNPs and CFSa-CsNPs also demonstrated the potency of suppressing TLR 2/4 (0.20 ± 0.01 and 0.12 ± 0.02, respectively) gene expression (p = 0.0019) and reduced Caco-2 cells attached bacteria to 526,000 ± 51,46 colony-forming units/mL (11.19%) (p < 0.0001).

CONCLUSION

Our study revealed that encapsulating CFSs within CsNPs enhances their vibriocidal activity by improving stability and enabling a controlled release mechanism at the site of interaction between the host and bacteria. Additionally, the simultaneous use of CFSb-CsNPs and CFSa-CsNPs exhibited superior vibriocidal potency against MDR V. cholerae O1 El Tor strains, indicating these combinations as a potential new approach against MDR bacteria.

The Role of the Gut Microbiome and Microbial Dysbiosis in Common Skin Diseases

Dermatoses are an increasingly common problem, particularly in developed countries. The causes of this phenomenon include genetic factors and environmental elements. More and more scientific reports suggest that the gut microbiome, more specifically its dysbiosis, also plays an important role in the induction and progression of diseases, including dermatological diseases. The gut microbiome is recognised as the largest endocrine organ, and has a key function in maintaining human homeostasis. In this review, the authors will take a close look at the link between the gut-skin axis and the pathogenesis of dermatoses such as atopic dermatitis, psoriasis, alopecia areata, and acne. The authors will also focus on the role of probiotics in remodelling the microbiome and the alleviation of dermatoses.

The pivotal role of Bifida Ferment Lysate on reinforcing the skin barrier function and maintaining homeostasis of skin defenses in vitro

BACKGROUND

The semiactive or inactive probiotics or their extracts used in dermatology have interesting properties to ameliorate signs of irritated skin and enhance the skin barrier. Bifidobacterium, as the most common probiotics, which has been found to be effective in reducing acne and improving the skin barrier function of atopic dermatitis. Bifida Ferment Lysate (BFL) can be obtained from Bifidobacterium by fermentation and extraction.

PURPOSE

In this study, we investigated the effect of a topically used BFL on the skin using in vitro evaluation methods.

RESULTS

The results showed that upregulation of skin physical barrier gene (FLG, LOR, IVL, TGM1, and AQP3) and antimicrobial peptide gene (CAMP and hBD-2) in HaCaT cells by BFL might be responsible for skin barrier resistance. In addition, BFL had strong antioxidant properties representing a dose-dependent increasing of the scavenging capacity of DPPH, ABTS, hydroxyl, and superoxide radicals. BFL treatment also fundamentally inhibited the intracellular ROS and MDA production and improved the activities of antioxidant enzymes (CAT and GSH-Px) in H2 O2 -stimulated HaCaT cells. As a good immunomodulatory factor, BFL efficiently decreased the secretion of IL-8 and TNF-α cytokines, and COX-2 mRNA expression in LPS-induced THP-1 macrophages.

CONCLUSION

BFL can strengthen the skin barrier function and stimulate skin barrier resistance, to reinforce the skin against oxidative stress and inflammatory stimuli.

Acne, Microbiome, and Probiotics: The Gut–Skin Axis

The objective of this narrative review was to check the influence of the human microbiota in the pathogenesis of acne and how the treatment with probiotics as adjuvant or alternative therapy affects the evolution of acne vulgaris. Acne is a chronic inflammatory skin disease involving the pilosebaceous units. The pathogenesis of acne is complex and multifactorial involving genetic, metabolic, and hormonal factors in which both skin and gut microbiota are implicated. Numerous studies have shown the bidirectionality between the intestinal microbiota and skin homeostasis, a communication mainly established by modifying the immune system. Increased data on the mechanisms of action regarding the relevance of Cutibacterium acnes, as well as the importance of the gut–skin axis, are becoming known. Diverse and varied in vitro studies have shown the potential beneficial effects of probiotics in this context. Clinical trials with both topical and oral probiotics are scarce, although they have shown positive results, especially with oral probiotics through the modulation of the intestinal microbiota, generating an anti-inflammatory response and restoring intestinal integrity, or through metabolic pathways involving insulin-like growth factor I (IGF-1). Given the aggressiveness of some standard acne treatments, probiotics should continue to be investigated as an alternative or adjuvant therapy.

Microbiome Modulation as a Therapeutic Approach in Chronic Skin Diseases

There is a growing quantity of evidence on how skin and gut microbiome composition impacts the course of various dermatological diseases. The strategies involving the modulation of bacterial composition are increasingly in the focus of research attention. The aim of the present review was to analyze the literature available in PubMed (MEDLINE) and EMBASE databases on the topic of microbiome modulation in skin diseases. The effects and possible mechanisms of action of probiotics, prebiotics and synbiotics in dermatological conditions including atopic dermatitis (AD), psoriasis, chronic ulcers, seborrheic dermatitis, burns and acne were analyzed. Due to the very limited number of studies available regarding the topic of microbiome modulation in all skin diseases except for AD, the authors decided to also include case reports and original studies concerning oral administration and topical application of the pro-, pre- and synbiotics in the final analysis. The evaluated studies mostly reported significant health benefits to the patients or show promising results in animal or ex vivo studies. However, due to a limited amount of research and unambiguous results, the topic of microbiome modulation as a therapeutic approach in skin diseases still warrants further investigation.

Carbopol-olive oil-based bigel drug delivery system of doxycycline hyclate for the treatment of acne

OBJECTIVE

The objective of this study was to prepare and evaluate the doxycycline hyclate containing bigel for the effective treatment of acne.

METHODS

Bigels are biphasic systems formed by water-based hydrogels and oil-based organogel. Carbopol 940 was used to prepare the hydrogel phase, whereas Span-60 and olive oil for the oleogel phase.

RESULTS

The microstructure of bigel confirmed the oil in water type emulsion formation. The average droplet size of formulations was found 15-50 µm, and a bell-shaped droplet distribution curve, rheological, or viscosity studies suggested that the consistency and stability of bigel decrease with high organogel concentration. Three formulations (F1, F2, and F3) of the different ratios of hydrogel:oleogel (60:40, 70:30, and 80:20) were prepared in which F1 was less stable compared to F2 and F3. The drug content of F2 and F3 was respectively 79.94 and 71.33%. Formulation F2 was found more effective as compared to F3 based on in vitro drug release studies. Bigel also showed better results during in vivo studies at the rabbit ear model, which reduce acne diameter up to 1.10 mm from 4.9 mm while gel reduced it up to 1.20 mm.

Antimicrobial and Immunomodulatory Effects of Bifidobacterium Strains: A Review

Bifidobacterium strains can provide several health benefits, such as antimicrobial and immunomodulatory effects. Some strains inhibit growth or cell adhesion of pathogenic bacteria, including multidrug-resistant bacteria, and their antibacterial activity can be intensified when combined with certain antibiotics. In addition, some strains of bifidobacteria reduce viral infectivity, leading to less epithelial damage of intestinal tissue, lowering the virus shedding titer, and controlling the release of antiviral substances. Furthermore, bifidobacteria can modulate the immune system by increasing immunoglobulins, and inducing or reducing pro- or antiinflammatory cytokines, respectively. In particular, these anti-inflammatory effects are helpful in the treatment of patients who are already suffering from infection or inflammatory diseases. This review summarizes the antimicrobial effects and mechanisms, and immunomodulatory effects of Bifidobacterium strains, suggesting the potential of bifidobacteria as an alternative or complementary treatment option.

Potential Role of the Microbiome in Acne: A Comprehensive Review

Acne is a highly prevalent inflammatory skin condition involving sebaceous sties. Although it clearly develops from an interplay of multiple factors, the exact cause of acne remains elusive. It is increasingly believed that the interaction between skin microbes and host immunity plays an important role in this disease, with perturbed microbial composition and activity found in acne patients. Cutibacterium acnes (C. acnes; formerly called Propionibacterium acnes) is commonly found in sebum-rich areas and its over-proliferation has long been thought to contribute to the disease. However, information provided by advanced metagenomic sequencing has indicated that the cutaneous microbiota in acne patients and acne-free individuals differ at the virulent-specific lineage level. Acne also has close connections with the gastrointestinal tract, and many argue that the gut microbiota could be involved in the pathogenic process of acne. The emotions of stress (e.g., depression and anxiety), for instance, have been hypothesized to aggravate acne by altering the gut microbiota and increasing intestinal permeability, potentially contributing to skin inflammation. Over the years, an expanding body of research has highlighted the presence of a gut–brain–skin axis that connects gut microbes, oral probiotics, and diet, currently an area of intense scrutiny, to acne severity. This review concentrates on the skin and gut microbes in acne, the role that the gut–brain–skin axis plays in the immunobiology of acne, and newly emerging microbiome-based therapies that can be applied to treat acne.

New Approach in Acne Therapy: A Specific Bacteriocin Activity and a Targeted Anti IL-8 Property in Just 1 Probiotic Strain, the L. salivarius LS03

GOALS

The aim of this research was to assess the antibacterial activity of Lactobacillus salivarius LS03 (DSM 22776) against Propionibacterium acnes and its anti-inflammatory properties by inhibiting P. acnes-induced interleukin-8 (IL-8) release.

BACKGROUND

Acne is the most common skin disease, causing significant psychosocial problems for those afflicted. Currently available agents for acne treatment, such as oral antibiotics, have limited use. Thus, development of novel agents to treat this disease is needed. In the generation of inflammatory lesions, proliferation of P. acnes in the obstructed follicles is critical. The administration of beneficial microorganisms represents a promising approach for treating several skin alterations and can have many favorable effects.

STUDY

For the inhibition assay, P. acnes was spread on Propionibacter Isolation Agar Base plates, and LS03-soaked disks were placed directly on the agar surface. Peripheral blood mononuclear cells, isolated from healthy volunteers, were preincubated with phytohemagglutinin 1 μg/mL for 1 hour and stimulated with the probiotic strains for 24 hours to simulate an in vitro IL-8 release model. The IL-8 concentration in the supernatants was analyzed in duplicate using ELISA Kit.

RESULTS

L. salivarius LS03 exerted a significant inhibitory capacity against the target pathogen strain. This antagonistic activity was primarily ascribable to the feature of LS03 strain of secreting active bacteriocins against P. acnes. Concerning the IL-8 analysis, 3 different L. salivarius strains were able to inhibit the release of this chemokine by 10% to 25%.

CONCLUSIONS

L. salivarius LS03 probiotic strain could be an alternative treatment to antibiotic/anti-inflammatory therapy in subjects presenting acne vulgaris.

Gut microbiota alterations in moderate to severe acne vulgaris patients

Acne vulgaris is a chronic inflammatory dermatosis affecting approximately 85% of adolescents. There are many factors contributing to the development of this ailment. A recent study indicated that gut microbiota takes part in the pathogenesis of acne. We aimed to investigate the link between acne vulgaris and gut microbiota. A total of 31 moderate to severe acne vulgaris patients and 31 healthy controls were enrolled. We collected their feces, and gut microbiota was evaluated by the hypervariable regions of 16S rRNA genes through high-throughput sequencing. We identified links between acne vulgaris and changes of gut microbiota. At the phylum level, Actinobacteria (0.89% in acne patients and 2.84% in normal controls, P = 0.004) was decreased and Proteobacteria (8.35% in acne patients and 7.01% in normal controls, P = 0.031) was increased. At the genus level, Bifidobacterium, Butyricicoccus, Coprobacillus, Lactobacillus and Allobaculum were all decreased. The observed difference in genera between acne patients and healthy controls provides a new insight into the link between gut microbiota changes and acne vulgaris risk.

Bifidobacteria and Their Molecular Communication with the Immune System

Bifidobacterium represents a genus within the phylum Actinobacteria which is one of the major phyla in the healthy intestinal tract of humans. Bifidobacterium is one of the most abundant genera in adults, but its predominance is even more pronounced in infants, especially during lactation, when they can constitute the majority of the total bacterial population. They are one of the pioneering colonizers of the early gut microbiota, and they are known to play important roles in the metabolism of dietary components, otherwise indigestible in the upper parts of the intestine, and in the maturation of the immune system. Bifidobacteria have been shown to interact with human immune cells and to modulate specific pathways, involving innate and adaptive immune processes. In this mini-review, we provide an overview of the current knowledge on the immunomodulatory properties of bifidobacteria and the mechanisms and molecular players underlying these processes, focusing on the corresponding implications for human health. We deal with in vitro models suitable for studying strain-specific immunomodulatory activities. These include peripheral blood mononuclear cells and T cell-mediated immune responses, both effector and regulatory cell responses, as well as the modulation of the phenotype of dendritic cells, among others. Furthermore, preclinical studies, mainly germ-free, gnotobiotic, and conventional murine models, and human clinical trials, are also discussed. Finally, we highlight evidence supporting the immunomodulatory effects of bifidobacterial molecules (proteins and peptides, exopolysaccharides, metabolites, and DNA), as well as the role of bifidobacterial metabolism in maintaining immune homeostasis through cross-feeding mechanisms.

The role of topical dermocosmetics in acne vulgaris

Acne is a common chronic inflammatory disease and treatment modalities based on acne severity are well established. The role of dermocosmetics in dermatology, and in particular acne, is becoming more important as more research elucidates the mechanisms of action of products in the pathogenesis of acne. Dermocosmetics have the potential to be used as monotherapy or in combination with medical treatment. Therefore, it has become important for dermatologists to understand dermocosmetics to effectively and appropriately advise patients on their use. The objective of this review was to provide new insights into the role of traditional and novel ingredients in dermocosmetics for the treatment of acne, based on the authors' objective assessment of the published literature. The type of products discussed include: those which have a sebostatic effect, such as topical antioxidants and niacinamide; agents targeting abnormal keratinization, such as salicylic acid, lipo-hydroxy acid, alpha-hydroxy acids, retinol-based products and linoleic acid; agents targeting Propionibacterium acnes, such as lauric acid; and anti-inflammatory agents such as nicotinamide, alpha-linolenic acid and zinc salts. Despite the scientific advances in understanding these cosmetic ingredients, there still remains a lack of rigorous controlled studies in this area.

Acne vulgaris, probiotics and the gut-brain-skin axis: from anecdote to translational medicine

Acne vulgaris has long been postulated to feature a gastrointestinal mechanism, dating back 80 years to dermatologists John H. Stokes and Donald M. Pillsbury. They hypothesised that emotional states (e.g. depression and anxiety) could alter normal intestinal microbiota, increase intestinal permeability, and contribute to systemic inflammation. They were also among the first to propose the use of probiotic Lactobacillus acidophilus cultures. In recent years, aspects of this gut-brain-skin theory have been further validated via modern scientific investigations. It is evident that gut microbes and oral probiotics could be linked to the skin, and particularly acne severity, by their ability to influence systemic inflammation, oxidative stress, glycaemic control, tissue lipid content, and even mood. This intricate relationship between gut microbiota and the skin may also be influenced by diet, a current area of intense scrutiny by those who study acne. Here we provide a historical background to the gut-brain-skin theory in acne, followed by a summary of contemporary investigations and clinical implications.