P98 Blood-based biomarkers of extracellular matrix turnover are elevated in patients with psoriasis compared with healthy controls

Abstract The extracellular matrix (ECM) is a non-cellular network in all tissues and organs. Collagens are the most abundant proteins in the ECM, and their role is to maintain the tissue architecture of the different layers of the skin. Blood-based biomarkers of ECM fragments have previously been shown to be diagnostic and pharmacodynamic in psoriatic arthritis (PsA) and spondylarthritis. This study aimed to investigate whether ECM biomarkers can differentiate between patients with moderate-to-severe psoriasis (PSO) and healthy controls (HCs) and to determine the potential of ECM biomarkers as pharmacodynamic biomarkers in patients with PSO. This was a case–control study of patients with moderate-to-severe PSO, defined as psoriasis area and severity index (PASI) ≥8, not receiving systemic anti-psoriatic treatment at inclusion, and age-, sex- and body mass index-matched HCs. From each participant, EDTA plasma was collected at inclusion and 3–6 months after successful treatment response (defined as PASI ≤ 2 after treatment) with adalimumab. A panel of 11 ECM biomarkers was measured in EDTA plasma using validated ELISAs and Immunodiagnostic systems automated chemiluminescent assays. A P-value below 0.05 was considered statistically significant. The differences in biomarker levels between patients with PSO and HC were analysed using an unpaired t-test. The pharmacodynamic effect in patients with PSO with successful treatment response (PASI ≤ 2), was analysed using a paired t-test. Pearson correlation was used to detect any potential association between biomarkers and PASI severity. The study comprised 59 patients with PSO and 52 HC. The median PASI among patients with PSO was 10.0 (8.0–36.8), and 15% (9 patients) had physician-diagnosed PsA. We observed significantly elevated levels of PRO-C3, assessing tissue fibrosis (P = 0.028), and PRO-C4, assessing epidermal basement membrane turnover (P = 0.014), in patients with PSO compared with HC. No differences were observed in the remaining biomarker levels between patients with PSO and HC. Furthermore, no correlations were identified between PASI and biomarker levels. A significantly elevated level of ELP-3 (P = 0.024), indicative of neutrophil activity and elastin degradation, was observed in the nine patients with PSO having PsA compared with HC. Notably, the successful treatment of nine patients with PSO using adalimumab did not significantly change PRO-C3 and PRO-C4 levels. The results demonstrated that the levels of PRO-C3 and PRO-C4 were elevated in patients with PSO compared with HC. However, treatment of psoriasis did not modulate these biomarkers. Our findings underline the need for further research to explore the potential of ECM biomarkers in psoriasis.