Soluble Lectin-Like Oxidized Low-Density Lipoprotein Receptor 1 Is Inversely Correlated with the Activity of ANCA-Associated Vasculitis

Lectin-like oxidized low-density lipoprotein (LDL) receptor 1 (LOX1) binds to oxidized LDL, which is associated with inflammation in various vascular disorders. Here, we aimed to investigate the potential of soluble LOX1 (sLOX1) as an indicator of antineutrophil cytoplasmic antibody-associated vasculitis (AAV) activity. Serum levels of sLOX1 in frozen samples from patients with AAV enrolled in a prospective observational cohort study at the Severance Hospital were measured using enzyme-linked immunosorbent assay. Clinical and laboratory data were collected on the date when the blood sampling was performed. The association between sLOX1 and clinical and laboratory data was assessed using Pearson's correlation analysis. The median age of the recruited 79 patients was 62.0 years, and 27 (34.2%) patients were men. The median Birmingham vasculitis activity score (BVAS), five-factor score, vasculitis damage index, and sLOX1 level were 6, 1, 3, and 911.9 pg/mL, respectively. Correlation analysis based on BVAS revealed that sLOX1 and total cholesterol were significantly inversely correlated with BVAS (r=−0.224, p=0.047 and r=−0.424, p<0.001, respectively). No significant correlations were observed between continuous variables and sLOX1 except for BVAS, although total cholesterol tended to correlate with sLOX1 (r=0.190, p=0.093). Additionally, sLOX1 was not influenced by sex, hypertension, diabetes mellitus, or the presence of pulmonary, cardiovascular, and renal involvement of AAV. In summary, sLOX1 was inversely correlated with BVAS in AAV patients, which is different from other vascular diseases or inflammatory diseases.