Association Between Serum Soluble Low‐Density Lipoprotein Receptor Levels and Metabolic Factors in Healthy Japanese Individuals

Background Soluble low-density lipoprotein receptor (sLDL-R) is formed by cleavage of the extracellular domain of low-density lipoprotein receptor (LDL-R). It is unclear whether serum sLDL-R is a marker of diseases associated with triglyceride (TG) metabolism. We investigated the association between serum sLDL-R concentrations and other biochemical parameters in healthy Japanese individuals. Methods Study subjects consisted of 102 healthy adult Japanese volunteers (42 men, 60 women) with body mass index (BMI) < 30 kg/m2 and serum TGs, LDL cholesterol (LDL-C), aspartate aminotransferase, alanine aminotransferase, γ-glutamyl transpeptidase, and glucose concentrations within normal ranges. Serum sLDL-R concentrations were determined by enzyme-linked immunosorbent assay and their correlations with biochemical parameters were analyzed. Results Mean serum sLDL-R concentration was 120.9 ± 39.9 ng/ml. Serum sLDL-R levels were significantly and positively correlated with BMI (rs = 0.252) and TG (rs = 0.408) and LDL-C (rs = 0.325) concentrations. Multiple regression analysis adjusted for age, gender, and smoking showed that BMI (β = 0.274), TG (β = 0.328), and LDL-C (β = 0.224) were factors independently correlated with sLDL-R levels. Conclusion Serum sLDL-R concentration may be a marker of diseases associated with TG metabolism. This is the first report to date describing the clinical relevance of sLDL-R.