Katerina Steventon discusses the microbial make-up of sebum-rich areas of skin and its relationship to acne
Since 2018, interest in the skin microbiome has been at the forefront of the skin care industry. This theme has enjoyed a tidal wave of interest from ingredient manufacturers and blue chip finished product manufacturers, as well as indie brands.
Gallinée, a British microbiome-focused brand, built its success on a patented complex of probiotics, prebiotics and lactic acid. Other brands followed suit, for example, Espa, whose ProBiome probiotic technology is clinically proven to nurture and support biodiversity and the skin’s natural bacterial balance.
But are manufacturers following a marketing trend, or seeking real scientific understanding?
Facial mapping provides an understanding of the relationship between a clinical skin condition, non-invasive biophysical parameters and the microbiome of a specific facial area. Although continuous mapping of skin hydration and barrier function has revealed the complexity of the facial micro-environments, comprehensive mapping is required to fully understand the microbiome.
The skin constitutes a site of interactions between the immune system and the microbiome. The skin microbial community is primarily formed by Corynebacteria, Propionibacteria and Staphylococci, and the interplay between the bacteria is essential for the maintenance of healthy skin.
Bacterial biofilms are networks that anable community-like living
Dry, hydrated and sebum-rich skin areas represent independent micro-environments with divergent communities.
The commensal bacterium Propionibacterium acnes, predominant in high-sebum areas, helps to regulate skin homeostasis and prevent colonisation from harmful pathogens. However, it can also act as an opportunistic pathogen, contributing to acne onset.
Factors other than bacteria contributing to acne are increased sebum production, a change in sebum composition and hyper-cornification of the sebaceous follicle, as well as hormones, genetics and stress.
At present, effective technologies such as retinoids or photodynamic therapy target the destruction of the sebaceous gland, reduce sebum production (as the nutrient source for bacteria), or address water within follicles to prevent microbial growth in acne-prone skin. But eradicating acne in the sebum-rich zone is difficult. Only recent advances in detection methods (fluorescent in situ hybridisation and immunofluorescent microscopy) have enabled researchers to visualise macro-colonies forming ‘biofilms’ in the sebaceous glands and the follicular walls of acne lesions.
Bacterial biofilms are networks that enable multicellular functions and community-like living, providing advantageous survival mechanisms such as virulence, pathogenesis or resistance to antibiotics.
The persistent nature of acne may be due to the formation of a biofilm in the sebaceous gland, encasing bacteria in a matrix and making them non-responsive to therapeutics. Currently, skin care products containing pre- or probiotics, live bacteria and bacteria lysates, aim to shift the microbial communities towards a healthy skin microbiome.
New antimicrobial strategies incorporate specific biofilm antagonists to disperse them and restore microbial homeostasis. An example is Pierre Fabre’s Ducray Keracnyl line, which contains the anti-biofilm compound Myrtacine that claims to help deconstruct the biofilm and restore antibiotic sensitivity. New initiatives in skin microbiomics are promising. Research into the microbiome of healthy skin is popular, yet emerging biofilm research represents a new, parallel microbial discipline. Both converge in skin conditions where the mechanisms of attachment, survival and propagation of bacteria allows for a complex and thorough understanding of the natural skin microbiome function.
DSM supports The Secret Life of Skin, a new scientific blog where diverse experts discuss new perspectives on the skin microbiome; and DSM has also made an investment in S-Biomedic, a Belgium-based business pioneering “a new approach to the cosmetic and therapeutic potential of the skin microbiome”. Meanwhile, the next Global Skin Microbiome Congress (organised by Kisaco Research) highlights the microbiome as 2019’s biggest trend in skin care.
As our understanding of skin microbiome and biofilms evolves, aiming for world-class research, rather than just following an exciting trend is essential.