Propionibacterium species and follicular keratinocyte activation in acneic and normal skin

Recent advances in understanding inflammatory acne: Deciphering the relationship between Cutibacterium acnes and Th17 inflammatory pathway

Acne vulgaris is a common chronic inflammatory skin disease of the pilosebaceous units. Four factors contribute to acne: hyperseborrhea and dysseborrhea, follicular hyperkeratinisation, skin microbiome dysbiosis and local immuno-inflammation. Recent key studies have highlighted a better understanding of the important role of Cutibacterium acnes (C. acnes) in the development of acne. Three major findings in the last decade include: (1) the ability of C. acnes to self-organize in a biofilm associated with a more virulent activity, (2) the loss of the C. acnes phylotype diversity and (3) the central role of the Th17 pathway in acne inflammation. Indeed, there is a close link between C. acnes and the activation of the Th17 immuno-inflammatory pathway at the initiation of acne development. These mechanisms are directly linked to the loss of C. acnes phylotype diversity during acne, with a predominance of the pro-pathogenic phylotype IA1. This specifically contributes to the induction of the Th17-mediated immuno-inflammatory response involving skin cells, such as keratinocytes, monocytes and sebocytes. These advancements have led to new insights into the underlying mechanisms which can be harnessed to develop novel treatments and diagnostic biomarkers. A major disadvantage of traditional treatment with topical antibiotics is that they induce cutaneous dysbiosis and antimicrobial resistance. Thus, future treatments would no longer aim to 'kill' C. acnes, but to maintain the skin microbiota balance allowing for tissue homeostasis, specifically, the restoration of C. acnes phylotype diversity. Here, we provide an overview of some of the key processes involved in the pathogenesis of acne, with a focus on the prominent role of C. acnes and the Th17-inflammatory pathways involved.

Reactive Oxygen Species and Antioxidant System in Selected Skin Disorders

The skin has a solid protective system that includes the stratum corneum as the primary barrier and a complete antioxidant defence system to maintain the skin's normal redox homeostasis. The epidermal and dermal cells are continuously exposed to physiological levels of reactive oxygen species (ROS) originating from cellular metabolic activities. Environmental insults, such as ultraviolet (UV) rays and air pollutants, also generate ROS that can contribute to structural damage of the skin. The antioxidant defence system ensures that the ROS level remains within the safe limit. In certain skin disorders, oxidative stress plays an important role, and there is an established interplay between oxidative stress and inflammation in the development of the condition. Lower levels of skin antioxidants indicate that oxidative stress may mediate the pathogenesis of the disorder. Accordingly, the total antioxidant level was also found to be lower in individuals with skin disorders in individuals with normal skin conditions. This review attempts to summarise the skin oxidant sources and antioxidant system. In addition, both skin and total antioxidant status of individuals with psoriasis, acne vulgaris, vitiligo and atopic dermatitis (AD), as well as their associations with the progression of these disorders will be reviewed.

Investigation of fungus at stratum corneum of patients with acne vulgaris

BACKGROUND

The pathophysiology of acne is complex and multifactorial. In recent years, fungal infections have increased significantly.

OBJECTIVES

The purpose of this study was to evaluate the role of fungi in the etiopathogenesis of acne vulgaris.

METHODS

This was a prospective case-control study. A total of 200 individuals (100 with acne vulgaris and 100 without acne vulgaris) were enrolled in the study. Direct microscopic investigation and culturing of the samples were done according to Clinical and Laboratory Standards Institute criteria. Descriptive analyses, independent sample t-tests, and chi-squared tests were used for statistical analysis. The subjects in the control group were paired by age and gender with the patients.

RESULTS

Direct microscopic examination revealed hyphae in the samples of all subjects with acne and in the samples of four of the healthy controls. The cultures of 18 of the patients with acne vulgaris were positive for the following: 6 with Aspergillus spp., 7 with Penicillium spp., 3 with Cladosporium spp., 1 with Candida spp., and 1 with Acremonium spp. In addition, Candida spp. was observed in the cultures of two of the healthy controls.

CONCLUSION

We conclude that fungi may be involved in the etiopathogenesis of acne vulgaris.

Skin dysbiosis and Cutibacterium acnes biofilm in inflammatory acne lesions of adolescents

Acne vulgaris is a common inflammatory disorder affecting more than 80% of young adolescents. Cutibacterium acnes plays a role in the pathogenesis of acne lesions, although the mechanisms are poorly understood. The study aimed to explore the microbiome at different skin sites in adolescent acne and the role of biofilm production in promoting the growth and persistence of C. acnes isolates. Microbiota analysis showed a significantly lower alpha diversity in inflammatory lesions (LA) than in non-inflammatory (NI) lesions of acne patients and healthy subjects (HS). Differences at the species level were driven by the overabundance of C. acnes on LA than NI and HS. The phylotype IA1 was more represented in the skin of acne patients than in HS. Genes involved in lipids transport and metabolism, as well as potential virulence factors associated with host-tissue colonization, were detected in all IA1 strains independently from the site of isolation. Additionally, the IA1 isolates were more efficient in early adhesion and biomass production than other phylotypes showing a significant increase in antibiotic tolerance. Overall, our data indicate that the site-specific dysbiosis in LA and colonization by virulent and highly tolerant C. acnes phylotypes may contribute to acne development in a part of the population, despite the universal carriage of the microorganism. Moreover, new antimicrobial agents, specifically targeting biofilm-forming C. acnes, may represent potential treatments to modulate the skin microbiota in acne.

The role of biofilm formation in the pathogenesis and antimicrobial susceptibility of Cutibacterium acnes

Cutibacterium acnes (previously known as Propionibacterium acnes) is frequently found on lipid-rich parts of the human skin. While C. acnes is most known for its role in the development and progression of the skin disease acne, it is also involved in many other types of infections, often involving implanted medical devices. C. acnes readily forms biofilms in vitro and there is growing evidence that biofilm formation by this Gram-positive, facultative anaerobic micro-organism plays an important role in vivo and is also involved in treatment failure. In this brief review we present an overview on what is known about C. acnes biofilms (including their role in pathogenesis and reduced susceptibility to antibiotics), discuss model systems that can be used to study these biofilms in vitro and in vivo and give an overview of interspecies interactions occurring in polymicrobial communities containing C. acnes.

Sebaceous immunobiology - skin homeostasis, pathophysiology, coordination of innate immunity and inflammatory response and disease associations

This review presents several aspects of the innovative concept of sebaceous immunobiology, which summarizes the numerous activities of the sebaceous gland including its classical physiological and pathophysiological tasks, namely sebum production and the development of seborrhea and acne. Sebaceous lipids, which represent 90% of the skin surface lipids in adolescents and adults, are markedly involved in the skin barrier function and perifollicular and dermal innate immune processes, leading to inflammatory skin diseases. Innovative experimental techniques using stem cell and sebocyte models have clarified the roles of distinct stem cells in sebaceous gland physiology and sebocyte function control mechanisms. The sebaceous gland represents an integral part of the pilosebaceous unit and its status is connected to hair follicle morphogenesis. Interestingly, professional inflammatory cells contribute to sebocyte differentiation and homeostasis, whereas the regulation of sebaceous gland function by immune cells is antigen-independent. Inflammation is involved in the very earliest differentiation changes of the pilosebaceous unit in acne. Sebocytes behave as potent immune regulators, integrating into the innate immune responses of the skin. Expressing inflammatory mediators, sebocytes also contribute to the polarization of cutaneous T cells towards the Th17 phenotype. In addition, the immune response of the perifollicular infiltrate depends on factors produced by the sebaceous glands, mostly sebaceous lipids. Human sebocytes in vitro express functional pattern recognition receptors, which are likely to interact with bacteria in acne pathogenesis. Sex steroids, peroxisome proliferator-activated receptor ligands, neuropeptides, endocannabinoids and a selective apoptotic process contribute to a complex regulation of sebocyte-induced immunological reaction in numerous acquired and congenital skin diseases, including hair diseases and atopic dermatitis.

Acne Vulgaris, Atopic Dermatitis and Rosacea: The Role of the Skin Microbiota-A Review

The skin harbors a huge number of different microorganisms such as bacteria, fungi and viruses, and it acts as a protective shield to prevent the invasion of pathogens and to maintain the health of the commensal microbiota. Several studies, in fact, have shown the importance of the skin microbiota for healthy skin. However, this balance can be altered by intrinsic and extrinsic factors, leading to the development of skin disease, such as acne vulgaris (AV), atopic dermatitis (AD) and rosacea(RS). Although these diseases are widespread and affect both adolescents and adults, the scientific correlation between these disorders and the skin microbiota and physiological parameters (TEWL, hydration and lipid composition) is still unclear. This review aims to investigate the current literature regarding the correlation between the skin microbiota and its imbalance underlying microbiological aspects, how the skin microbiota changes over the course of the disease and the current possible treatments. The following reported studies show a general imbalance of the bacterial flora. For this reason, more in-depth studies are necessary to explore the different subspecies and strains involved in all three diseases.

In vivo model of Propionibacterium (Cutibacterium) spp. biofilm in Drosophila melanogaster

OBJECTIVES

Acne vulgaris is a common inflammatory disorder of the pilosebaceous unit and Propionibacterium acnes biofilm-forming ability is believed to be a contributing factor to the disease development. In vivo models mimicking hair follicle environment are lacking. The aim of this study was to develop an in vivo Propionibacterium spp. biofilm model in Drosophila melanogaster (fruit fly).

METHODS

We created a sterile line of D. melanogaster able to sustain Propionibacterium spp. biofilms in the gut. In order to mimic the lipid-rich, anaerobic environment of the hair follicle, fruit flies were maintained on lipid-rich diet. Propionibacterium spp. biofilms were visualized by immunofluorescence and scanning electron microscopy. We further tested if the biofilm-dispersal activity of DNase I can be demonstrated in the developed model.

RESULTS

We have demonstrated the feasibility of our in vivo model for development and study of P. acnes, P. granulosum and P. avidum biofilms. The model is suitable to evaluate dispersal as well as other agents against P. acnes biofilm.

CONCLUSIONS

We report a novel in vivo model for studying Propionibacterium spp. biofilms. The model can be suitable for both mechanistic as well as interventional studies.

Combining Visible Light and Non-Focused Ultrasound Significantly Reduces Propionibacterium acnes Biofilm While Having Limited Effect on Host Cells

Bacterial biofilms are highly resistant to antibiotics and have been implicated in the etiology of 60%–80% of chronic microbial infections. We tested a novel combination of low intensity ultrasound and blue light against biofilm and planktonic bacteria. A laboratory prototype was built which produced both energies uniformly and coincidently from a single treatment head, impinging upon a 4.45 cm² target. To demonstrate proof of concept, Propionibacterium acnes biofilms were cultured on Millicell hanging inserts in 6-well plates. Hanging inserts with biofilms were treated in a custom exposure chamber designed to minimize unwanted ultrasound reflections. Coincident delivery of both energies demonstrated synergy over either alone, killing both stationary planktonic and biofilm cultures of P. acnes. Reduction in biofilm bacteria was dose dependent on exposure time (i.e., energy delivered). P. acnes biofilms were significantly reduced by dual energy treatment (p < 0.0001), with a >1 log₁₀ reduction after a 5 min (9 J/cm²) and >3 log₁₀ reduction after a 30 min (54 J/cm²) treatment (p < 0.05). Mammalian cells were found to be unaffected by the treatment. Both the light and the ultrasound energies are at levels previously cleared by the FDA. Therefore, this combination treatment could be used as a safe, efficacious method to treat biofilm related syndromes.

Antioxidant Activity of Hydrogen Water Mask Pack Composed of Gel-Type Emulsion and Hydrogen Generation Powder

In this study, hydrogen generation powder samples were prepared using zinc carbonate as a precursor, at a temperature varying from 400 to 700 °C in H₂ atmosphere, and were characterized in terms of antioxidant activity. The concentration of dissolved hydrogen obtained by the powder samples was measured using a dissolved hydrogen meter as a function of time. In addition, the antioxidant activity of the samples was evaluated based on the Oyaizu’s method, removal rate of ·OH radicals, and ferric reducing antioxidant power. Finally, the hydrogen mask pack was fabricated using the hydrogen generation powder sample and gel-type emulsion. In the clinical test on the mask pack, the effect of the mask on skin aging was characterized and compared to that of a commercial sample. The skin densities of the participants in the experimental group and the control group increased by 18.41% and 9.93% after 4 weeks, respectively. The improved skin density of the participants who used the hydrogen mask pack in the experimental group, might be attributed to the recovery effect of the hydrogen molecule in the mask pack on the denatured thick skin layer.

Piceatannol Inhibits P. acnes-Induced Keratinocyte Proliferation and Migration by Downregulating Oxidative Stress and the Inflammatory Response

The Cutibacterium acnes (also called Propionibacterium acnes, P. acnes)-induced proliferation and migration of keratinocytes contribute to acne vulgaris (AV), which is a common inflammatory skin disease that causes physical and psychological impairments. Piceatannol (3, 5, 3', 4'-tetrahydroxy-trans-stilbene, PCT) is naturally present in many human diets and plays antioxidant and anti-inflammatory roles that inhibit cell proliferation and migration. We aimed to analyse the functions and underlying mechanisms of PCT in P. acnes-stimulated keratinocytes. First, PCT showed no toxicity against the normal human keratinocyte cell line HaCaT but inhibited P. acnes-induced HaCaT cell proliferation. Next, PCT promoted the nuclear translocation and target gene transcription of the antioxidant transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2), thereafter decreasing intracellular reactive oxygen species (ROS) levels. In addition, PCT inhibited the nuclear translocation of p65 [a subunit of nuclear factor kappa B (NF-κB)] and the secretion of pro-inflammatory cytokines, including interleukin-6 (IL-6), tumour necrosis factor-α (TNF-α) and interleukin-8 (IL-8). Finally, a transfection assay showed that PCT inhibited P. acnes-induced HaCaT cell proliferation and migration by activating the antioxidant Nrf2 pathway and inhibiting the inflammatory NF-κB pathway. Our data suggested that PCT alleviated P. acnes-induced HaCaT cell proliferation and migration through its antioxidant and anti-inflammatory roles, suggesting the potential of PCT to treat AV.

High bacterial colonization and lipase activity in microcomedones

BACKGROUND

Although acne vulgaris has a multifactorial aetiology, comedogenesis and bacteria colonization of the pilosebaceous unit are known to play a major role in the onset of inflammatory acne lesions. However, many aspects remain poorly understood such as where and when is the early stage of the Propionibacterium acnes colonization in follicular unit? Our research aimed at providing a precise analysis of microcomedone's structure to better understand the interplay between Propionibacterium acnes and follicular units, and therefore, the role of its interplay in the formation of acne lesions.

METHODS

Microcomedones were sampled using cyanoacrylate skin surface stripping (CSSS). Their morphology was investigated with multiphoton imaging and their ultrastructure with scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Bacterial lipase activity in the microcomedones was quantified using a dedicated enzymatic test as well as a Fourier Transform Infra-Red (FTIR) analysis. The porphyrin produced by bacteria was analysed with HPTLC and fluorescence spectroscopy.

RESULTS

The imaging analysis showed that microcomedones' structure resembles a pouch, whose interior is mostly composed of lipids with clusters of bacteria and whose outer shell is made up of corneocyte layers. The extensive bacteria colonization is clearly visible using TEM. Even after sampling, clear lipase activity was still seen in the microcomedone. A high correlation, r = .85, was observed between porphyrin content measured with HPTLC and with fluorescence spectroscopy. These observations show that microcomedones, which are generally barely visible clinically, already contain a bacterial colonization.

A Real-Life, International, Observational Study Demonstrating The Efficacy Of A Cosmetic Emulsion In The Supportive Care Of Mild-To-Moderate Facial Acne

Purpose

Cosmetic emulsions are increasingly being used as supportive care products to alleviate the severe side effects and improve the clinical outcomes associated with conventional acne treatments. The objectives of this study were to determine, in a real-life setting, the global effectiveness of an emulsion with antiseborrheic, keratolytic and anti-Propionibacterium acnes activities as an adjunct to anti-acne therapy, and to evaluate the effect of the product on acne severity, noninflammatory and inflammatory lesions, hyperseborrhea, skin irritation and patient quality of life (QoL). Tolerance of the product was also assessed.

Patients and methods

This international observational study involved 3960 patients aged 12 years and over with mild-to-moderate acne. The conventional acne prescriptions for these patients were either initiated at inclusion or were reviewed. Reviewed prescriptions may have been left unchanged, switched, or an addition made to ongoing treatment. At inclusion, participants were instructed to apply the cosmetic product daily for 2–3 months in combination with their medical acne treatment.

Results

After 2 to 3 months of use, the combined therapy resulted in moderate-to-large improvements in acne in over 75% of the patients whose acne prescriptions were left unchanged (n=859). The combination treatment led to an improvement in acne severity (−38.3% change in the mean investigator’s global assessment score; p<0.0001) and QoL (−38.3% change in the mean Cardiff acne disability index score; p<0.0001), and reduced noninflammatory and superficial inflammatory lesions (−35.3% and −47.0%, respectively; p<0.0001), hyperseborrhoea (−40.6%; p<0.0001) and skin irritation (−37.2%; p<0.0001). Tolerance was very good.

Conclusion

Use of the cosmetic emulsion combined with conventional acne therapy significantly improved clinical outcomes and patient QoL, and was very well tolerated. The combined therapy may have improved patient satisfaction, leading to improved patient adherence and higher rates of therapeutic success.

Models for acne: A comprehensive study

Acne vulgaris (AV) is the familiar chronic skin ailment affecting most of the individuals. This multifarious, disease involves the bacterium gram-positive, anaerobic Propionibacterium acnes (P. acnes) which resides on skin microflora, and participated in acne inflammation and acne lesions. The object of this review is to discuss presently available in vitro, ex vivo, and in vivo models to evaluate the cosmetic formulations that are developed for dealing and prevention of acne formation. These various available models offer new chances for further research on biologically active materials, drugs & pharmaceutical as well as cosmetics for acne treatment.

A review of microscopy-based evidence for the association of Propionibacterium acnes biofilms in degenerative disc disease and other diseased human tissue

PURPOSE

Recent research shows an increasing recognition that organisms not traditionally considered infectious in nature contribute to disease processes. Propionibacterium acnes (P. acnes) is a gram-positive, aerotolerant anaerobe prevalent in the sebaceous gland-rich areas of the human skin. A ubiquitous slow-growing organism with the capacity to form biofilm, P. acnes, recognized for its role in acne vulgaris and medical device-related infections, is now also linked to a number of other human diseases. While bacterial culture and molecular techniques are used to investigate the involvement of P. acnes in such diseases, definitive demonstration of P. acnes infection requires a technique (or techniques) sensitive to the presence of biofilms and insensitive to the presence of potential contamination. Fortunately, there are imaging techniques meeting these criteria, in particular, fluorescence in situ hybridization and immunofluorescence coupled with confocal laser scanning microscopy, as well as immunohistochemistry.

METHODS

Our literature review considers a range of microscopy-based studies that provides definitive evidence of P. acnes colonization within tissue from a number of human diseases (acne vulgaris, degenerative disc and prostate disease and atherosclerosis), some of which are currently not considered to have an infectious etiology.

RESULTS/CONCLUSION

We conclude that P. acnes is an opportunistic pathogen with a likely underestimated role in the development of various human diseases associated with significant morbidity and, in some cases, mortality. As such, these findings offer the potential for new studies aimed at understanding the pathological mechanisms driving the observed disease associations, as well as novel diagnostic strategies and treatment strategies, particularly for degenerative disc disease. These slides can be retrieved under Electronic Supplementary Material.

Intra-peritoneal abscess after an abdominal hysterectomy involving Cutibacterium avidum (former Propionibacterium avidum) highly resistant to clindamycin

Cutibacterium avidum is a gram-positive anaerobic rod belonging to the cutaneous group of human bacteria with preferential colonization of sweat glands in moist areas. The microorganism rarely cause disease, generally delayed prosthetic joint infections (PJIs). We describe the second case of intraperitoneal abscess by C. avidum after an abdominal surgery in an obese female patient and the first case after a non-prosthetic abdominal surgery due to a highly clindamycin resistant strain in a patient with underling conditions. The patient was successfully treated with surgical drainage and beta-lactam antibiotics. Although rare and apparently non-pathogenic, C. avidum may be involved in infections, especially in some high-risk patients with obesity who have undergone surgical incision involving deep folder of the skin. The microorganism was identified by phenotypic methods, MALDI-TOF MS and 16S rRNA gene sequencing. Susceptibility test should be performed in C. avidum because high level resistance to clindamycin could be present. We present a literature review of C. avidum infections.

No evidence for follicular keratinocyte hyperproliferation in acne lesions as compared to autologous healthy hair follicles

Abnormal hyperkeratinization in sebaceous hair follicles has long been believed to play an important role in acne pathogenesis. Several early reports purported to provide histological evidence for hyperproliferation of keratinocytes in acne lesions by showing a higher expression of the Ki67 as well as certain keratins. The evidence is, however, not robust, and a number of methodological and technical limitations can be identified in these studies. In this study, we looked at the expression of proliferation, mitosis and apoptosis markers directly at acne skin lesions in 66 patients with acne vulgaris. Ki67 was assessed using immunohistochemistry and α-tubulin, phospho-histone H3 and cleaved-PARP with immunofluorescence microscopy. Allogenic unaffected hair follicles from the same acne patients were used as an internal control. In both acne and control hair follicles, the α-tubulin staining was universal, approaching 100% cells and showed no signs of changed assembly. Expression of cleaved-PARP-the apoptosis marker-was a rare event. Cell proliferation rate measured by the expression of Ki67 and phospho-histone H3 was virtually identical between acne and the two control groups. Our findings show the absence of increased keratinocyte proliferation in acne vulgaris. Alternative mechanisms are likely responsible for infundibular hyperkeratinization in acne pathogenesis.

Propionibacterium acnes and Acne Vulgaris: New Insights from the Integration of Population Genetic, Multi-Omic, Biochemical and Host-Microbe Studies

The anaerobic bacterium Propionibacterium acnes is believed to play an important role in the pathophysiology of the common skin disease acne vulgaris. Over the last 10 years our understanding of the taxonomic and intraspecies diversity of this bacterium has increased tremendously, and with it the realisation that particular strains are associated with skin health while others appear related to disease. This extensive review will cover our current knowledge regarding the association of P. acnes phylogroups, clonal complexes and sequence types with acne vulgaris based on multilocus sequence typing of isolates, and direct ribotyping of the P. acnes strain population in skin microbiome samples based on 16S rDNA metagenomic data. We will also consider how multi-omic and biochemical studies have facilitated our understanding of P. acnes pathogenicity and interactions with the host, thus providing insights into why certain lineages appear to have a heightened capacity to contribute to acne vulgaris development, while others are positively associated with skin health. We conclude with a discussion of new therapeutic strategies that are currently under investigation for acne vulgaris, including vaccination, and consider the potential of these treatments to also perturb beneficial lineages of P. acnes on the skin.

Androgens modulate keratinocyte differentiation indirectly through enhancing growth factor production from dermal fibroblasts

BACKGROUND

The main pathogenesis of acne vulgaris is increase in sebum production and abnormal keratinization of the hair infundibulum. The androgens are involved in acne pathogenesis by modulating sebaceous glands to enhance sebum production. However, the molecular mechanisms of abnormal keratinization of the hair infundibulum are not fully elucidated.

OBJECTIVE

We hypothesized that the androgens affect the dermal fibroblasts, another androgen receptor-positive cells in the skin, resulting in abnormal keratinization through keratinocyte-fibroblast interaction.

METHODS

We investigated effects of androgens and estrogens on growth factors expressions by RT-PCR and western blot analysis in human fibroblast (hFB), human keratinocyte (hKC), and fibroblast-keratinocyte co-culture. In vivo, we examined the growth factor expression in acne lesions compared to normal hair follicles by laser-assisted confocal microscope.

RESULTS

In vitro, androgens but not estrogens significantly increased amphiregulin (AREG), epiregulin (EREG), fibroblast growth factor (FGF) 10, and insulin-like growth factor binding protein (IGFBP) 5 mRNA and protein expressions in human fibroblasts but not in keratinocytes. In vivo, AREG, EREG, FGF10, and IGFBP5 were more abundant in acne lesion compared to normal facial skin. FGF10 suppressed cytokeratin 1 and cytokeratin 10 expression in hKC, which was along with the decreased ratio of cytokeratin 10 against cytokeratin 14 in acne lesions compared to normal facial skin. Also, DHT suppressed cytokeratin 1 and cytokeratin 10, in fibroblast-keratinocyte co-culture similarly to the effect of FGF10 to hKC.

CONCLUSION

These observations suggested that androgens enhance growth factors production from dermal fibroblasts, and growth factors from fibroblasts alter keratinocyte differentiation in acne lesion.

Clinical and Biological Features of Cutibacterium (Formerly Propionibacterium) avidum, an Underrecognized Microorganism

The recent description of the genus Cutibacterium has altered the taxonomy of Propionibacterium species. These organisms still belong to the genera of the skin coryneform group, and the most-studied species remains Cutibacterium acnes. Cutibacterium avidum is also a known skin commensal. This underrecognized microorganism can, however, act as a pathogen after bacterial seeding and can be considered opportunistic, causing either superficial or deep/invasive infections. It can cause numerous infections, including but not limited to breast infections, skin abscesses, infective endocarditis, and device-related infections. The ecological niche of C. avidum is clearly different from that of other members of the genus: it is found in the axillary region or at wet sites rather than in dry, exposed areas, and the number of microorganisms increases during puberty. Historically, it has been used for its ability to modulate the immune response and for its antitumor properties. Conventional microbial culture methods and identification processes allow for its accurate identification and characterization. Thanks to the modern omics tools used for phylogenomic approaches, understanding C. avidum pathogenesis (including host-bacterium interactions and virulence factor characterization) is becoming easier, allowing for more thorough molecular characterization. These analyses have revealed that C. avidum causes diverse diseases mediated by multiple virulence factors. The recent genome approach has revealed specific genomic regions within this species that are involved in adherence and biofilm formation as well as fitness, survival, and defense functions. Numerous regions show the presence of phages and horizontal gene transfer. C. avidum remains highly sensitive to a broad spectrum of antibiotics, such as β-lactams, fluoroquinolones, macrolides, and rifampin, although erythromycin and clindamycin resistance has been described. A long-term treatment regimen with a combination of antibiotics is required to successfully eliminate the remaining adherent bacteria, particularly in the case of deep infections after debridement surgery.

Developing an in vitro artificial sebum model to study Propionibacterium acnes biofilms

AIM

The aim of the present study was to develop a new model system to study Propionibacterium acnes biofilms. This model should be representative for the conditions encountered in the pilosebaceous unit.

METHODS AND RESULTS

The new model, consists of an artificial sebum pellet supported by a silicone disc. Sebum pellets were inoculated with various P. acnes strains isolated from both normal and acneic skin. Growth and biofilm formation was verified by conventional plating at different time points, as well as by resazurin assays and fluorescence microscopy after LIVE/DEAD staining. The artificial sebum pellets were also used in assays to measure the production of certain virulence factors implicated in the pathogenesis of acne, including lipase, protease and the presence of CAMP factors.

CONCLUSION

The artificial sebum model can sustain biofilm growth of P. acnes, as was determined by increasing CFU counts for up to 1 week after inoculation. Metabolic activity and biofilm formation were confirmed using resazurin staining and fluorescence microscopy respectively. The production of virulence factors in this model was demonstrated as well.

Measuring acne using Coproporphyrin III, Protoporphyrin IX, and lesion-specific inflammation: an exploratory study

Propionibacterium acnes: (P. acnes) produce Porphyrins; however, fluorescence measurement of Porphyrins from Ultraviolet-A (UVA) images has failed to establish a correlation. Acne clinical research and imaging has ignored the spectral excitation-emission characteristics and the exact pattern of the Porphyrins synthesized by P. acnes. In this exploratory study, for the first time, the possible relationships of Coproporphyrin III (CpIII) and Protoporphyrin IX (PpIX) fluorescence as well as acne lesion-specific inflammation measurements with clinical signs of acne are investigated. Furthermore, the sensitivity of these measurements in tracking and differentiating the known treatment effects of Benzoyl Peroxide (BPO) 5%, and combination of Clindamycin + BPO are also evaluated. Comedonal and papulopustular lesions identified by investigators during a live assessment of 24 mild-to-severe acne subjects were compared with fluorescence and inflammation measurements obtained from analysis of VISIA^®-CR images. CpIII fluorescence spots showed a strong correlation (r = 0.69-0.83), while PpIX fluorescence spots showed a weak correlation (r = 0.19-0.27) with the investigators' comedonal lesion counts. A strong correlation was also observed between the investigators' papulopustular lesion counts and acne lesion-specific inflammation (r = 0.76). Our results suggest that CpIII fluorescence and acne lesion-specific-inflammation measurement can provide objective indication of comedonal and papulopustular acne severity, respectively. Furthermore, these measurements may be more sensitive and specific in evaluating treatment effects and early signs of acne lesion progression compared to investigators' lesion counts.

The balance of metagenomic elements shapes the skin microbiome in acne and health

Studies have emphasized the importance of disease-associated microorganisms in perturbed communities, however, the protective roles of commensals are largely under recognized and poorly understood. Using acne as a model disease, we investigated the determinants of the overall virulence property of the skin microbiota when disease- and health-associated organisms coexist in the community. By ultra-deep metagenomic shotgun sequencing, we revealed higher relative abundances of propionibacteria and Propionibacterium acnes phage in healthy skin. In acne patients, the microbiome composition at the species level and at P. acnes strain level was more diverse than in healthy individuals, with enriched virulence-associated factors and reduced abundance of metabolic synthesis genes. Based on the abundance profiles of the metagenomic elements, we constructed a quantitative prediction model, which classified the clinical states of the host skin with high accuracy in both our study cohort (85%) and an independent sample set (86%). Our results suggest that the balance between metagenomic elements, not the mere presence of disease-associated strains, shapes the overall virulence property of the skin microbiota. This study provides new insights into the microbial mechanism of acne pathogenesis and suggests probiotic and phage therapies as potential acne treatments to modulate the skin microbiota and to maintain skin health.

A systematic review and meta-analysis on Staphylococcus aureus carriage in psoriasis, acne and rosacea

Staphylococcus aureus might amplify symptoms in chronic inflammatory skin diseases. This study evaluates skin and mucosal colonization with S. aureus in patients with psoriasis, acne and rosacea. A systematic literature search was conducted. Both odds ratios (OR) for colonization in patients versus controls and the prevalence of colonization in patients are reported. Fifteen articles about psoriasis and 13 about acne (12 having a control group) were included. No study in rosacea met our inclusion criteria. For psoriasis, one study out of three controlled studies showed increased skin colonization (OR 18.86; 95 % confidence interval [CI] 2.20-161.99). Three out of the five studies that reported on nasal colonization showed significant ORs varying from 1.73 (95 % CI 1.16-2.58) to 14.64 (95 % CI 2.82-75.95). For acne one of the three studies that evaluated skin colonization reported a significant OR of 4.16 (95 % CI 1.74-9.94). A relation between nasal colonization and acne was not found. Limitations in study design and low sample sizes should be taken into consideration when interpreting the results. Colonisation with S. aureus seems to be increased in patients with psoriasis. This bacterial species, known for its potential to induce long-lasting inflammation, might be involved in psoriasis pathogenesis. Information on acne is limited. Prospective controlled studies should further investigate the role of S. aureus in chronic inflammatory skin diseases.

Photodynamic therapy inhibit Fibroblast Growth Factor-10 induced keratinocyte differentiation and proliferation through ROS in Fibroblast Growth Factor Receptor-2b pathway

5-aminolevulinic acid-photodynamic therapy (ALA-PDT) is known to be effective in several skin diseases such as acne, actinic keratoses, condyloma acuminata. However, some detailed mechanisms of ALA-PDT to treat these skin diseases still remain elusive. In this study, we aimed to investigate mechanism of ALA-PDT in in-vitro and in-vivo models. For in vitro, we use human keratinocyte cell line (HaCaT) cells. CCK-8 was used to detect cell proliferation activity, immunofluorescence and western blotting method to detect the content of keratin (K)1, K6, K16, protein kinase C (PKC), fibroblast growth factor receptor-2b (FGFR2b) protein, ELISA and RT-PCR to detect expression of interleukin (IL) 1α in the cell supernatant, and detect reactive oxygen species (ROS). For in vivo, we use 20 rabbits to induce hyperkeratosis acne model in their ear. Dermatoscope was used to see follicle hyperkeratosis and skin biopsy to analyze histology and immunohistochemical of PKC, FGFR2b, K1, K6 and K16. Results from this study suggest that ROS stimulated by ALA-PDT lead to inhibition of FGFR2b pathway in PKC downstream to cause reduction of IL1α expression, and eventually, keratinocytes differentiation and proliferation. Our data thus reveal a treatment mechanism of ALA-PDT underlying hyperkeratosis related dermatoses.

Peptide Regulation of Skin Fibroblast Functions during Their Aging In Vitro

The effect peptides KE, KED, AED and AEDG on proliferation (Ki-67), regeneration and aging (CD98hc), apoptosis (caspase-3), and extracellular matrix remodeling (MMP-9) in skin fibroblasts during their aging in culture were studied by immunofluorescent confocal microscopy. All studied peptides inhibited MMP-9 synthesis that increases during aging of skin fibroblasts and enhanced the expression of Ki-67 and CD98hc that are less intensively synthesized during cell aging. Peptides AED and AEDG suppressed caspase-dependent apoptosis that increases during aging of cell cultures.

Profile of clindamycin phosphate 1.2%/benzoyl peroxide 3.75% aqueous gel for the treatment of acne vulgaris

Acne vulgaris is a common and chronic skin disease, and is a frequent source of morbidity for affected patients. Treatment of acne vulgaris is often difficult due to the multifactorial nature of this disease. Combination therapy, such as that containing clindamycin and benzoyl peroxide, has become the standard of care. Several fixed formulations of clindamycin 1% and benzoyl peroxide of varying concentrations are available and have been used with considerable success. The major limitation is irritation and dryness from higher concentrations of benzoyl peroxide, and a combination providing optimal efficacy and tolerability has yet to be determined. Recently, a clindamycin and benzoyl peroxide 3.75% fixed combination formulation was developed. Studies have suggested that this formulation may be a safe and effective treatment regimen for patients with acne vulgaris. Here, we provide a brief review of acne pathogenesis, benzoyl peroxide and clindamycin, and profile a new Clindamycin-BP 3.75% fixed combination gel for the treatment of moderate-to-severe acne vulgaris.