Longitudinal profiling of the gut microbiome in patients with psoriatic arthritis and ankylosing spondylitis: a multicentre, prospective, observational study

Abstract

Background : Psoriasis is a chronic inflammatory disease of the skin affecting 2-3% ofUK population. 30% of people affected by psoriasis will develop a distinct form ofarthritis within 10 years of the skin condition onset. Although the pathogenesis ofpsoriatic arthritis is still unknown, there is a genetic predisposition triggered byenvironmental factors. Limited but convincing evidence link the gut microbiome topsoriatic arthritis. The Microbiome in Psoriatic ARThritis (Mi-PART) study propose is tocharacterise the microbiome-metabolic interface in patients affected by psoriaticarthritis to deepen our understanding of the pathogenesis of the disease.Methods : This is a multicentre, prospective, observational study. Psoriatic arthritis (n= 65) and ankylosing spondylitis (n = 30) patients will be recruited in addition to acontrol group of healthy volunteers (n = 30). Patients eligibility will be evaluated againstthe Criteria for Psoriatic Arthritis (CASPAR), the Bath Ankylosing Spondylitis ActivityIndex (BASDAI) and the healthy volunteers who fulfil study inclusion and exclusioncriteria.Information regarding their medical and medication history, demographics, diet andlifestyle will be collected. All the participants in the study will be asked to complete a 7-day food diary, to provide stool samples and to complete quality of life questionnaires.Routine clinical laboratory tests will be performed on blood and urine samples. Patientsand healthy volunteers with gastrointestinal symptoms, previous history of cancer,gastrointestinal surgery in the previous 6 months or alcohol abuse will be excludedfrom the study.Discussion : The aim of this trial is to characterise the microbiome of psoriatic arthritispatients and to compare it with microbiome of healthy volunteers and of patient withankylosing spondylitis in order to define if different rheumatologic conditions areassociated with characteristic microbiome profiles. Investigating the role of themicrobiome in the development of psoriatic arthritis could deepen our understanding ofthe pathogenesis of the disease and potentially open the way to new therapies.