Psoriasis: Disrupted gut-skin axis

An evolving field is the impact of microbiota and the intestinal barrier on the pathophysiology of chronic inflammatory diseases, including psoriasis and psoriatic arthritis. Psoriasis contributes to the disruption of the intestinal barrier integrity and to the translocation of bacterial metabolites. This can activate the inflammatory response, leading to the exacerbation of skin lesions.

Increasing evidence from experimental and clinical studies suggests an important role for the interaction between an altered intestinal microbiome (dysbiosis), intestinal barrier damage, and the immune system in the pathogenesis of psoriasis. These findings triggered research towards the gut-skin axis.

Dr Mariusz Sikora (Medical University of Warsaw, Poland) and colleagues studied the influence of the disease activity of psoriasis on the intestinal barrier permeability and the blood concentration of bacterial metabolites and its clinical implications, such as the presence of gastrointestinal symptoms and psoriasis comorbidities [1].

Patients with mild-to-severe plaque psoriasis (n=120) were included. Intestinal barrier integrity was assessed using serum concentrations of claudin-3, a modulator of intestinal tight junctions, and with intestinal fatty acid-binding protein, a marker of enterocyte damage. The levels of these markers were significantly higher in patients with psoriasis compared with healthy controls (P<0.001 and P<0.05, respectively).

The concentration of the gut microbiota-associated metabolites trimethylamine N-oxide (TMAO) and indoxyl sulphate were measured with high-performance liquid chromatography. The concentration of TMAO positively correlated with the cardiovascular risk, calculated according to the Framingham and QRISK-2 scales (r=0.679; P<0.05). Translocation of bacterial metabolites through an altered intestinal barrier in psoriasis is a potential mechanism linking gut dysbiosis to increased cardiovascular risk.

Further research on the intestinal barrier is needed to get a better understanding of the impact this may have on skin lesions. Potential treatments that are impacting gut microbiota, such as faecal transplantation, probiotics, prebiotics, antibiotics, and molecules affecting intestinal barrier permeability are being intensively studied as therapies that can potentially break the vicious circle affecting the disrupted gut-skin axis in patients with psoriasis.

1. Sikora M. Intestinal barrier and gut microbiota-derived metabolites in the pathophysiology of psoriasis. Poster P58, 6^th World Psoriasis & Psoriatic Arthritis Conference, 30 June–3 July 2021.

 

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Posted on 17 September 202116 September 2021