Microbiome, Probiotics & Gut Nutrition

The Skin Microbiome

The Nobel laureate Joshua Lederberg suggested using the term ‘human Microbiome’ to describe the collective genome of our indigenous microorganisms (micro flora) colonizing the whole body. The skin is a complex barrier organ made of a symbiotic relationship between microbial communities and host tissue via complex signals provided by the innate and the adaptive immune systems.  It is constantly exposed to various endogenous and exogenous factors which impact this balanced system potentially leading to inflammatory skin conditions comprising infections, allergies or autoimmune diseases started using modern methods such as pyro sequencing assays of bacterial 16S RNA genes to identify and characterize the different microorganisms present on the skin, to evaluate the bacterial diversity and their relative abundance and to understand how microbial diversity may contribute to skin health and dermatological conditions, Three main sampling methods are currently used to harvest the resident skin micro biota The skin barrier and the micro biota act like a shield that protects the body against external aggressions. There is a balanced interplay between the host and resident and/or transient bacterial populations. This balance is continuously affected by intrinsic (host) and extrinsic (environmental) factors that alter the composition of skin microorganism communities and the host skin barrier function. Altering this equilibrium is called dysbiosis. Underlying pathobiology or genetically determined variations in stratum corneum properties might result in a dysbiosis that changes the abundance and diversity of commensal species, which disturbs skin barrier function and aggravates chronic skin diseases such as atopic dermatitis and psoriasis dysbiosis does not only occur between bacteria, disequilibrium between bacteria and commensal fungi strains on the scalp has been observed in subjects prone to dandruff the impact of environmental factors such as climate, including temperature and UV exposure but also of lifestyle, including alcoholism or nutrition on microbial communities remains to be elucidated. Indeed, ultraviolet B and C light have been reported to be bactericidal, while excessive alcohol consumption has been shown to diminish host resistance and nutrient and vitamin deficiency has been shown to impact on the skin micro biota balance, resulting in infection and skin barrier disturbance, Cosmetics, hygiene products, makeup, and moisturizers have also been implicated in modifying the skin Microbiome, Radiotherapy and chemotherapy used to treat cancer may also impact the micro biota. Therefore, improving the knowledge about the skin  Microbiome may open new perspectives in the management of the healthy and diseased skin and of its Microbiome.