Multiplexed serum biomarker signature integrating metallomics, Vitamin D, and MMP-9 for precision diagnosis of chronic plaque psoriasis.

BACKGROUND AND

OBJECTIVES

Psoriasis represents a chronic inflammatory condition associated with immuno-mediated and metabolic alterations. This case control study investigated correlations between serum 25-hydroxyvitamin D (25OHD) and matrix metalloproteinase-9 (MMP-9).

METHODS

This research was carried out on 142 participants comprised of 71 with plaque psoriasis and 71 healthy controls matched for age and sex. Serum concentrations of 25-hydroxyvitamin D and MMP-9 were analyzed using Enzyme-Linked Immunosorbent Assay (ELISA), and elements via Inductively Coupled Plasma Mass Spectrometry (ICP-MS). Serum elements were quantified using an Agilent 7900 ICP-MS following a 20 fold dilution of samples in a diluent containing 1% HNO₃ and internal standards (Sc, Ge, Rh, Ir). The method was calibrated using a multi-element standard (IV-ICPMS-71A, 0-200 µg/L), and analysis was performed in collision cell mode (He gas, 4 mL/min) to reduce polyatomic interference.

RESULTS

Compared with healthy controls, levels of MMP-9 were substantially higher in patients (2.59 ± 2.70 versus 1.24 ± 1.45 pg/mL; p < 0.001, FDR = 0.008), whereas circulating 25-hydroxyvitamin D was significantly lower (21.0 ± 8.2 versus 25.0 ± 11.4 ng/mL; p = 0.017, FDR = 0.046). No significant correlation was observed between 25-hydroxyvitamin D and MMP-9 (ρ = -0.07, p = 0.35). Additionally, psoriatic patients exhibited significant reduction in serum iron (Fe) and zinc (Zn) levels whereas serum cupper (Cu) and barium (Ba) concentrations were elevated. A 25-biomarker LASSO model provided excellent discrimination for psoriasis status: AUC = 0.944, 95% CI 0.90-0.98; sensitivity = 94.4%, specificity = 85.9%. Other significant metal alterations included lower Fe (2.24 ± 1.51 vs. 3.29 ± 2.47 ppm; Hedges' g = +0.51) and Zn (0.56 ± 0.14 vs. 0.64 ± 0.18 ppm; g = +0.50), and higher Cu (1.81 ± 0.83 vs. 1.53 ± 0.60 ppm; g = -0.39) and Ba (0.297 ± 0.087 vs. 0.267 ± 0.064 ppm; g = -0.39).

CONCLUSION

Psoriatic patients showed higher MMP-9 and lower levels of vitamin D, with specific metal disturbances; however, no link between 25-hydroxyvitamin D and MMP-9 has been found, with the implication of distinct pathways in the pathophysiology of psoriasis supporting the potential of a multi biomarker model that requires further validation.