The skin and the digestive tract may seem to be a hundred thousand miles apart, but they are in fact closely related. Because there is a bridge between them, this bridge is called “intestine-skin axis” in medical science.
As far as psoriasis is concerned, the state of the flora in the intestinal tract of patients is closely related to the occurrence, development and regression of psoriasis.
1. Mechanism related to psoriasis combined with digestive disease
Both skin and intestine are vascular and neurologically rich organs, which have important immune regulation, defense and neuroendocrine functions and play a vital role in maintaining physiological balance.
(1) Intestinal flora and intestinal skin axis
The human intestinal tract is inhabited by a large number of intestinal flora with complex composition, mainly including probiotics, conditionally pathogenic bacteria and pathogenic bacteria. Once the balance between them is disrupted, i.e., intestinal flora is dysregulated, more harmful bacteria will be produced, leading to increased intestinal barrier function and permeability, which in turn activates effector T cells and disrupts their balance with immunosuppressive regulatory T cells, resulting in impaired immune function of the body and negatively affecting skin function. Negative effects on skin function.
Of course, the relationship between skin and intestine is bidirectional, in addition to the intestine may act on the skin, the skin may also affect the intestinal health, which is related to genetic and environmental factors.
(2) Psoriasis and digestive tract diseases
Some experimental studies have shown a crossover of susceptibility genes in patients with psoriasis and inflammatory bowel disease, which leads to the speculation that psoriasis is connected to systemic inflammatory responses and immune problems caused by intestinal flora disorders.
In addition to this, certain environmental factors, as well as immune pathways, are jointly involved in the pathogenesis of both diseases, such as Th17 cells and their cytokines, which play a major role in the development of psoriasis, and are also involved in the physiopathological processes of inflammatory bowel disease.
In addition, the diversity and relative abundance of intestinal flora in patients with psoriasis are also significantly reduced in comparison to the healthy population, with Bifidobacterium spp., Braunschweiger spp. and Clostridium faecalis spp. being significant.
At the same time, the content of short-chain fatty acids in the stool of psoriasis patients was also significantly reduced compared with healthy individuals. Short-chain fatty acids can regulate the number and function of T-cell population by promoting the regulation of T-cell induction and adaptation in the colonic environment, and they have an irreplaceable role in promoting the function of immune homeostasis.
This shows that there is a relationship between psoriasis and intestinal flora as well as intestinal diseases such as inflammatory bowel disease.
2.Treatment related to psoriasis combined with digestive disease
Intestinal flora disorders are involved in the physiopathological process of inflammatory and immune diseases, so correcting intestinal flora dysbiosis and maintaining intestinal microecological balance are new targets for the prevention and treatment of psoriasis.
(1) Start through probiotics and prebiotics
Probiotics are a class of active microorganisms that produce beneficial effects on the host by regulating the intestinal micro-ecological balance, while prebiotics have been used with good results in atopic dermatitis, acne and wound healing.
Both have immunomodulatory effects on the skin and can enhance skin barrier repair by reducing skin bacterial load and antagonizing invasive commensalism.
Probiotics Chart
A six-day animal study found that Lactobacillus probiotic-65 improved the severity of imiquimod-induced psoriasis lesions in mice and reduced the expression levels of psoriasis-related pro-inflammatory cytokines.
This suggests that Lactobacillus may not only alleviate clinical symptoms but also reduce the levels of pro-inflammatory cytokines. However, this is only an initial strategic strategy and needs to be supported by clinical evidence from a large sample.
(2) Learn more about the fecal transplantation technique
Fecal transplantation
Fecal transplantation is currently the most direct way to increase beneficial intestinal bacteria, change the structure of the disordered intestinal flora and re-establish the intestinal environment, which can be used to restore the balance of intestinal flora, so to some extent, this may be a new treatment strategy for psoriasis.
(3) Dietary interventions remain important
Studies have found that a high-fat diet exacerbates imiquimod-induced psoriasis-like dermatitis in mice, and patients need to reduce the intake of such foods as appropriate and increase the intake of anti-inflammatory compounds such as dietary fiber and polyphenolic foods as appropriate.
The skin and the digestive tract, as important physiological barriers of the body, implicitly interact with each other while protecting the body from invasive exogenous pathogenic agents. Therefore, when treating and controlling psoriasis, we should not only focus on the treatment of skin surface damage, but also go deep inside the organism to explore new treatment and control strategies for psoriasis.
References
[1]Xu Xiaorong,Gong Jian,Wang Jing,Wu Jiaming,Liu Qiao. Advances in experimental research on the correlation between intestinal flora and psoriasis[J]. Journal of Practical Medicine,2020,36(09):1153-1156.