Project 442966

Psoriasis is a common chronic inflammatory skin disease that affects more than a million Canadians. Many patients with psoriasis also have involvement of the joints and develop a specific form of arthritis called psoriatic arthritis. Patients with psoriasis and psoriatic arthritis have flaky, red, itchy skin, joint destruction, limitation of function and poor quality of life. It is important to accurately determine how active psoriasis and psoriatic arthritis is so that appropriate treatment is initiated and further damage to joints reduced. However, current methods of assessing disease activity are imprecise, subjective and labour intensive. We do not have a good understanding of pathways of metabolism underlying active disease. Our purpose is to confirm whether small molecules (metabolites) and pathways that we have previously identified reliably measure disease activity. To achieve our objectives, we will test blood samples collected from patients with psoriatic arthritis who have undergone careful assessment of disease activity by ultrasound scan of their joints. We will also collect blood samples from patients with PsA who have the full range of severity of skin psoriasis. We will then subject the samples to novel laboratory methods to identify metabolites associated with active skin and joint disease. We will also determine if these blood metabolites are able to identify patients with psoriatic arthritis who have mild, moderate, and severe disease as measured by routine clinical methods. The study will confirm previously identified small molecules and pathways driving inflammation in the skin and joints in patients with psoriasis. In future we will confirm that biomarker-based assessment is better than currently used clinical methods. Once confirmed we will have better means of measuring disease activity and will help make treatment decision making easier and better informed, thus leading to better outcomes for patients with psoriatic disease.