The updates and implications of cutaneous microbiota in acne

Unraveling the Potential of Vitamin B3-Derived Salts with a Salicylate Anion as Dermal Active Agents for Acne Treatment

This study is focused on the utilization of naturally occurring salicylic acid and nicotinamide (vitamin B3) in the development of novel sustainable Active Pharmaceutical Ingredients (APIs) with significant potential for treating acne vulgaris. The study highlights how the chemical structure of the cation significantly influences surface activity, lipophilicity, and solubility in aqueous media. Furthermore, the new ionic forms of APIs, the synthesis of which was assessed with Green Chemistry metrics, exhibited very good antibacterial properties against common pathogens that contribute to the development of acne, resulting in remarkable enhancement of biological activity ranging from 200 to as much as 2000 times when compared to salicylic acid alone. The molecular docking studies also revealed the excellent anti-inflammatory activity of N-alkylnicotinamide salicylates comparable to commonly used drugs (indomethacin, ibuprofen, and acetylsalicylic acid) and were even characterized by better IC50 values than common anti-inflammatory drugs in some cases. The derivative, featuring a decyl substituent in the pyridinium ring of nicotinamide, exhibited efficacy against Cutibacterium acnes while displaying favorable water solubility and improved wettability on hydrophobic surfaces, marking it as particularly promising. To investigate the impact of the APIs on the biosphere, the EC50 parameter was determined against a model representative of crustaceans─Artemia franciscana. The majority of compounds (with the exception of the salt containing the dodecyl substituent) could be classified as "Relatively Harmless" or "Practically Nontoxic", indicating their potential low environmental impact, which is essential in the context of modern drug development.

A dermocosmetic product containing the sap of oat plantlets and Garcinia mangostana extract improves the clinical signs of acne

BACKGROUND

Acne vulgaris is a common chronic inflammatory disorder of the pilosebaceous unit, characterized by papules, pustules and/or nodules manifesting primarily on the face and/or upper back that can leave scars, post-inflammatory hyperpigmentation (PIH) and erythema (PIE).

OBJECTIVE

To evaluate the anti-inflammatory properties of a protein-free sap extruded from Rhealba® oat plantlets and a Garcinia mangostana extract on Cutibacterium acnes-induced inflammation in vitro and assess the tolerability and efficacy of a dermocosmetic product containing these actives in subjects with mild-to-moderate acne.

METHODS

Monocyte-derived dendritic cells (Mo-DCs) from acne patients were stimulated with a planktonic culture of C. acnes and cytokine production was evaluated before and after addition of the test extracts by RT-PCR and ELISA. The clinical study was conducted in subjects with mild-to-moderate acne who applied the product to their face and upper back twice-daily for 2 months.

RESULTS

Cutibacterium acnes-induced IL-6, IL-12p40, IL-10 and TNFα synthesis was reduced by the addition of the Garcinia mangostana extract and oat sap in vitro. The clinical study included 54 subjects. The 2-month, twice-daily application of the test product to the whole face and acne-affected areas on the upper back was well tolerated. It led to significant decreases in the number of retentional (-21% for 69% of subjects at D57) and inflammatory (-35% for 79% of subjects at D57) acne lesions, as well as a decrease in Global Acne Evaluation severity scores (2.5 at D1, 2.2 at D29 and 2.1 at D57). The dermatologist also rated the product as effective or very effective in most subjects with PIE (82%; n = 33/40) and PIH (70%; n = 8/11) at D57.

CONCLUSION

The actives demonstrated anti-inflammatory effects in vitro, and the dermocosmetic product showed good clinical efficacy and tolerability in subjects with mild-to-moderate acne, supporting the use of this product in acne management.

Vitis vinifera L. Leaf Extract, a Microbiota Green Ally against Infectious and Inflammatory Skin and Scalp Diseases: An In-Depth Update

The skin microbiota, with its millions of bacteria, fungi, and viruses, plays a key role in balancing the health of the skin and scalp. Its continuous exposure to potentially harmful stressors can lead to abnormalities such as local dysbiosis, altered barrier function, pathobiont overabundance, and infections often sustained by multidrug-resistant bacteria. These factors contribute to skin impairment, deregulation of immune response, and chronic inflammation, with local and systemic consequences. In this scenario, according to the needs of the bio-circular-green economy model, novel harmless strategies, both for regulating the diverse epidermal infectious and inflammatory processes and for preserving or restoring the host skin eubiosis and barrier selectivity, are requested. Vitis vinifera L. leaves and their derived extracts are rich in plant secondary metabolites, such as polyphenols, with antioxidant, anti-inflammatory, antimicrobial, and immunomodulatory properties that can be further exploited through microbe-driven fermentation processes. On this premise, this literature review aims to provide an informative summary of the most updated evidence on their interactions with skin commensals and pathogens and on their ability to manage inflammatory conditions and restore microbial biodiversity. The emerging research showcases the potential novel beneficial ingredients for addressing various skincare concerns and advancing the cosmeceutics field as well.

Microbiome Modulation in Acne Patients and Clinical Correlations

BACKGROUND

The imbalance of skin microbiota in acne can induce changes leading to induction or to aggravation of chronic inflammatory lesions; complex mechanisms are involved. Cutibacterium acnes (C. acnes) ribotypes RT4 and RT5 express more biofilm and are associated with inflammatory acne lesions. C. acnes RT6 is a non-acne ribotype, beneficial for the skin.

OBJECTIVES

In an open clinical trial, acne adults were included and assessed clinically at baseline and at month 2 using the Investigator Global Assessment of Acne (IGA) score. A topical emulsion was applied twice daily for 2 months (M2) in each included patient. In the same series of acne patients, skin swab samples were collected from acne patients at baseline and M2 from lesional and non-lesional skin; skin swabs were collected for the metagenomic long-read analysis of microbiota.

MATERIALS AND METHODS

Acne patients with a gravity score IGA of >1<3 were included in this pilot study. An emulsion of O/W formulated with vegetal extract of Umbelliferae associated with a polysaccharide at 1% was applied twice daily for 2 months. At baseline and M2 clinical assessments were made; skin swab samples were also taken for microbiota analysis from lesional and non-lesional skin in each included patient. Extractions of genomic DNA (gDNA) from swab samples from baseline and from M2 were made, followed by full-length (V1-V9) amplification of the 16S rDNA and sequencing of amplicon libraries for strain-level bacterial community profiling.

RESULTS

In a series of 32 adult acne patients, the mean initial IGA scale was 3.1; at M2 the IGA scale was 1.5 (p < 0.001). The mean decrease in acne lesions was by 63%. Microbiome metagenomic long-read analysis in these series was mainly dominated by C. acnes followed by Staphylococcus epidermidis (S. epidermidis). The density of C. acnes ribotypes RT6 (non-acne strain) was increased at M2 compared to baseline and the density of ribotypes C. acnes RT1 to RT5 was decreased at M2, compared to baseline (p < 0.0001). S. epidermidis ribotypes (1 to 36) were non significantly increased at M2, compared to baseline (p < 0.1).

CONCLUSIONS

In a series of 32 acne patients that applied an emulsion based on vegetal extract of Umbelliferae and a polysaccharide at 1% twice daily, a significant clinical improvement in IGA scale for acne lesions was seen at M2, compared to baseline (p < 0.0001). The clinical improvement was correlated with an improvement in skin microbiome at M2 compared to baseline, indicated by the increase in the relative abundance of non-acne strain of C. acnes ribotype 6 and of the decrease in the relative abundance of acne strains ribotypes C. acnes RT1 to RT5.

Updates on Topical Dyad and Triple Combination Therapies Approved for Acne Vulgaris

Acne vulgaris is a multifaceted disease characterized by inflammatory and noninflammatory lesions. Topical combination therapies offer a multifaceted approach to acne treatment, with synergistic effects and a broad spectrum of action against multiple factors in acne pathogenesis in one single formulation. Clindamycin phosphate/benzoyl peroxide/adapalene, a combination therapy consisting of clindamycin phosphate 1.2%, benzoyl peroxide (BPO) 3.1%, and adapalene 0.15%, is a novel treatment, the only FDA-approved triple combination drug that offers effective treatment of acne vulgaris. This review aims to provide information on clindamycin phosphate/benzoyl peroxide/adapalene and review the literature on combination topical acne medications approved in the United States. This search was conducted on topical combination therapies for acne, their efficacy, adverse effects, and impacts on quality of life with a specific focus on the newly approved clindamycin phosphate/benzoyl peroxide/adapalene and its sub-component dyads, along with other combinations. PubMed, SCOPUS, Embase, Cochrane, and Web of Science databases were searched for publications in 2018-2023. Primary sources were given priority, and secondary sources such as other reviews were considered to supplement any missing information. It was found that various topical dyad and triad combinations exist for acne vulgaris, including adapalene/BPO, tazarotene/clindamycin, clindamycin/BPO, adapalene/clindamycin, topical tretinoin/azelaic acid, topical tretinoin/BPO, and clindamycin phosphate/benzoyl peroxide/adapalene. Dyad and triple combinations represent a promising, convenient solution for acne management, potentially improving patient adherence due to its single formulation. Clindamycin phosphate/benzoyl peroxide/adapalene exhibited significantly high efficacy in treating both inflammatory and noninflammatory lesions, a minimal side effect profile, although no significant changes in quality-of-life measures. Further research is indicated to assess its long-term efficacy and impact on other acne metrics such as cost, scarring, psychosocial implications, and impact on diverse patient populations.

Illuminating microflora: shedding light on the potential of blue light to modulate the cutaneous microbiome

Cutaneous diseases (such as atopic dermatitis, acne, psoriasis, alopecia and chronic wounds) rank as the fourth most prevalent human disease, affecting nearly one-third of the world's population. Skin diseases contribute to significant non-fatal disability globally, impacting individuals, partners, and society at large. Recent evidence suggests that specific microbes colonising our skin and its appendages are often overrepresented in disease. Therefore, manipulating interactions of the microbiome in a non-invasive and safe way presents an attractive approach for management of skin and hair follicle conditions. Due to its proven anti-microbial and anti-inflammatory effects, blue light (380 - 495nm) has received considerable attention as a possible 'magic bullet' for management of skin dysbiosis. As humans, we have evolved under the influence of sun exposure, which comprise a significant portion of blue light. A growing body of evidence indicates that our resident skin microbiome possesses the ability to detect and respond to blue light through expression of chromophores. This can modulate physiological responses, ranging from cytotoxicity to proliferation. In this review we first present evidence of the diverse blue light-sensitive chromophores expressed by members of the skin microbiome. Subsequently, we discuss how blue light may impact the dialog between the host and its skin microbiome in prevalent skin and hair follicle conditions. Finally, we examine the constraints of this non-invasive treatment strategy and outline prospective avenues for further research. Collectively, these findings present a comprehensive body of evidence regarding the potential utility of blue light as a restorative tool for managing prevalent skin conditions. Furthermore, they underscore the critical unmet need for a whole systems approach to comprehend the ramifications of blue light on both host and microbial behaviour.

Peiminine Exerts Its Anti-Acne Effects by Regulating the NF-κB Pathway

Peiminine is the main natural alkaloid compound extracted from the Chinese herb Fritillaria. Although peiminine is known for its antioxidant and anti-inflammatory effects in conditions such as mastitis and arthritis, its impact on inflammation induced by Cutibacterisum acnes (C. acnes) has not been explored. The aim of this study was to investigate the effect of peiminine on C. acnes-induced inflammatory responses in the skin and to identify the underlying mechanism involved. We discovered that peiminine inhibits the C. acnes-induced expression of inflammatory mediators such as pro-interleukin-1β (pro-IL-1β), cyclooxygenase-2 (COX-2), tumor necrosis factor-α (TNF-α), and interleukin-6 (IL-6) in mouse bone marrow-derived macrophages (BMDMs). Peiminine suppressed the activation of nuclear factor-kappa B (NF-κB) without affecting the activation of mitogen-activated protein kinase (MAPK) pathways such as JNK, ERK, and p38 MAPK. In addition, we found that peiminine suppressed inflammatory cytokine expression and ameliorated histological symptoms in C. acnes-induced mouse skin. Our study is the first to provide evidence that peiminine has an inhibitory effect on acne, and it points toward the potential of incorporating peiminine into cosmetic and pharmaceutical formulations for acne treatment.

Acne Transcriptomics: Fundamentals of Acne Pathogenesis and Isotretinoin Treatment

This review on acne transcriptomics allows for deeper insights into the pathogenesis of acne and isotretinoin's mode of action. Puberty-induced insulin-like growth factor 1 (IGF-1), insulin and androgen signaling activate the kinase AKT and mechanistic target of rapamycin complex 1 (mTORC1). A Western diet (hyperglycemic carbohydrates and milk/dairy products) also co-stimulates AKT/mTORC1 signaling. The AKT-mediated phosphorylation of nuclear FoxO1 and FoxO3 results in their extrusion into the cytoplasm, a critical switch which enhances the transactivation of lipogenic and proinflammatory transcription factors, including androgen receptor (AR), sterol regulatory element-binding transcription factor 1 (SREBF1), peroxisome proliferator-activated receptor γ (PPARγ) and signal transducer and activator of transcription 3 (STAT3), but reduces the FoxO1-dependent expression of GATA binding protein 6 (GATA6), the key transcription factor for infundibular keratinocyte homeostasis. The AKT-mediated phosphorylation of the p53-binding protein MDM2 promotes the degradation of p53. In contrast, isotretinoin enhances the expression of p53, FoxO1 and FoxO3 in the sebaceous glands of acne patients. The overexpression of these proapoptotic transcription factors explains isotretinoin's desirable sebum-suppressive effect via the induction of sebocyte apoptosis and the depletion of BLIMP1(+) sebocyte progenitor cells; it also explains its adverse effects, including teratogenicity (neural crest cell apoptosis), a reduced ovarian reserve (granulosa cell apoptosis), the risk of depression (the apoptosis of hypothalamic neurons), VLDL hyperlipidemia, intracranial hypertension and dry skin.