Figure 4.

Mechanisms of the interaction at the gut-skin axis. This illustration represents the underlying mechanisms of gut-skin interaction. Various dietary components, illnesses, lifestyles, prebiotics, antibiotics, probiotics, and novel biological drugs can alter gut microbial communities. A. The alteration can lead to dysbiosis, which can further (i) decrease the gut mucus layer, (ii) results in the passage of microbes through the intestinal barrier, (iii) cause the production of toxic products, (iv) induce harmful effects by neurotransmitters of the gut microbes or the host, (v) produce B cell hyperresponsiveness, (vi) impair T cell differentiation, (vii) create low levels of IgA secretion. B. Dysbiotic gut microbes, toxic products, neurotransmitters, and altered immune cells pass through the circulatory system turning the skin condition from healthy (left) to dysbiotic (right). (i) Healthy skin possesses a balanced composition of microbes and proper quantities of human and microbial AMPs. (ii) A dysbiotic skin condition is induced by the pathogen due to improper immune system functioning and low quantities of human and microbial AMPs. C. Dysbiotic skin microbes trigger skin inflammation and can be involved in the onset of a variety of skin illnesses. This illustration is based on ¹⁵and ¹⁶and created with BioRender.com (2022).