Bacterial Metabolites: A Link between Gut Microbiota and Dermatological Diseases

Abstract

Dysbiosis has been identified in many dermatological conditions (e.g., psoriasis, atopic dermatitis, systemic lupus erythematosus). One of the ways by which the microbiota affect homeostasis is through microbiota-derived molecules (metabolites). There are three main groups of metabolites: short-chain fatty acids (SCFAs), tryptophan metabolites, and amine derivatives including trimethylamine N-oxide (TMAO). Each group has its own uptake and specific receptors through which these metabolites can exert their systemic function. This review provides up-to-date knowledge about the impact that these groups of gut microbiota metabolites may have in dermatological conditions. Special attention is paid to the effect of microbial metabolites on the immune system, including changes in the profile of the immune cells and cytokine disbalance, which are characteristic of several dermatological diseases, especially psoriasis and atopic dermatitis. Targeting the production of microbiota metabolites may serve as a novel therapeutic approach in several immune-mediated dermatological diseases.

The Clinical Significance of Serum Biomarkers of the Intestinal Barrier in Systemic Sclerosis: A Cross-Sectional Study

“…Available techniques of modulation of microbiota include probiotics, prebiotics, and fecal microbiota transplantation. These methods have been intensively studied in a number of dermatological conditions and are known to improve the gut barrier [34][35][36]. An improvement of the intestinal barrier by the mentioned interventions leads to a decrease in intestinal permeability and can be an effect of elevated expression of proteins of tight junction complexes in intestinal epithelial cells, stimulation of the proliferation of intestinal epithelial cells, and an increased secretion of mucins, which protect enterocytes from stressors [34][35][36].…”

“…These methods have been intensively studied in a number of dermatological conditions and are known to improve the gut barrier [34][35][36]. An improvement of the intestinal barrier by the mentioned interventions leads to a decrease in intestinal permeability and can be an effect of elevated expression of proteins of tight junction complexes in intestinal epithelial cells, stimulation of the proliferation of intestinal epithelial cells, and an increased secretion of mucins, which protect enterocytes from stressors [34][35][36]. Such attempts were also made in systemic sclerosis and were associated mainly with the improvement of gastrointestinal symptoms [37][38][39][40][41].…”

From gut to skin: exploring the potential of natural products targeting microorganisms for atopic dermatitis treatment

“…One of the most critical functions of SCFAs in the pathogenesis of hypersensitivity is their capacity to enhance the integrity of intestinal and epithelial barriers. 103 The microbiota exerts its functions through these metabolites, with SCFAs, for instance, being responsible for regulating immune responses via increasing Tregs. 104 These metabolites can accumulate subcutaneously or alter intestinal mucosal permeability into the bloodstream, thereby downregulating keratin expression and altering keratin-forming cell differentiation, skin hydration capacity, and epidermal barrier function, eventually affecting the onset and progression of AD.…”

“…111 These findings suggest that bacterial metabolites play a significant role in pruritus of AD, and targeting these metabolites may be a promising approach for pruritus treatment. 103…”

Psoriasis and gut microbiota: A Mendelian randomization study

“…The typical clinical symptoms include well-defined erythematous, pruritic plaques that can cover large areas of the skin. [5][6][7][8] Microbiota, 9 which has been present in the human environment since birth, plays a crucial role in human pathology and physiology.…”