INulin-type β-fructans supplementation to modulate gut microbiota and assessment of its effects on health status and GUT-SKIN axis parameters in patients with psoriasis (INGUTSKIN): the 8-week, randomised, double-blind, placebo-controlled clinical study protocol

A strong, bidirectional association exists between gastrointestinal health and skin homeostasis in many chronic skin inflammations, including psoriasis (PS). It is postulated that, apart from genetic predisposition, the rise of local and systemic immune response in PS could be a consequence of intestinal dysbiosis associated with increased intestinal permeability. We hypothesised that restoring gut microbiome homeostasis and proper functioning of the intestinal barrier in PS patients would alleviate the inflammatory symptoms and severity of the skin lesions. The study aims to determine the effect of chicory-derived inulin-type β-fructans (ITFs) on health-related parameters in mild PS patients through molecular analysis of gut microbiota characteristics and assessment of a wide spectrum of biomarkers of the gut-skin axis. The randomised, placebo-controlled clinical trial (RCT) with prebiotic intervention is proposed. Adult mild PS patients (Psoriasis Area and Severity Index; PASI < 10) with a body mass index (BMI) < 30 kg/m2 following an omnivore diet will be enrolled into the trial and randomized to one of two groups: prebiotic (receiving 15 g/per day of ITFs) or placebo (receiving 15 g/per day of maltodextrin) for 8 weeks in a double-blind manner. Body composition, clinical parameters, nutritional status, quality of life, immune and inflammatory parameters, intestinal barrier permeability, characteristics of faecal bacteria, and metabolic dysfunction markers will be determined at baseline and after supplementation. Compliance and adverse reactions will be evaluated. The dysregulation in intestinal microbiota-host interplay is connected with the development of many chronic skin inflammations, including PS. A proper diet is a relatively easy-modifiable factor that may influence the course of PS treatment. Among dietary components, prebiotics have garnered our interest as ingredients with a proven ability to enhance host health by modulating the gut microbiota. With the proposed RCT, we will determine the impact of ITFs on gut microbiota characteristics and evaluate whether this ITFs-induced microbiota modulation is an effective method to alleviate inflammation and reduce the severity of skin lesions in PS. We expect that the RCT results will enable the introduction of personalised dietary therapy with prebiotic ITFs, which, unlike other PS therapies, would not pose a high risk of side effects. ClinicalTrials.gov Registration Number: NCT05971992.