Circulating levels of selenium-binding protein 1 (SELENBP1) are associated with risk for major adverse cardiac events and death

Objective: Selenium-binding protein 1 (SELENBPI) is an intracellular protein with variable expression in response to cellular stress. As the selenium (Se) status is affected by inflammation and hypoxia, we hypothesized that SELENBP1 contributes to disease-specific Se metabolism. To test this hypothesis, a quantitative assay was developed and used to monitor SELENBP1 in patients with acute coronary syndrome (ACS). Materials and methods: SELENBP1 was expressed, antibodies were generated and a luminometric immuno assay (LIA) was established and characterized. Serum samples were collected from controls (n = 37) and patients (n = 85) admitted to the Chest Pain Unit with suspected ACS. Blood samples were available from time of first medical contact in the ambulance, at admission to hospital, and after 2, 4, 6 and 12-36 h. Results: Circulating SELENBPI was close to limit of detection in healthy controls and elevated in patients with suspected ACS. SELENBPI was unrelated to other biomarkers of myocardial damage such as troponin T or aspartate aminotransferase. Serum SELENBPI enabled a categorization of patients on first medical contact as either high-risk or low-risk for major adverse cardiac events (MACE) or death, when using 0.8 nmol/l as threshold. The odds-ratios (OR) for MACE and death were OR = 11 (95% CI: 2-49, p = 0.0022) and OR = 12 (2-74, p = 0.014), respectively. Conclusions: Until now, SELENBPI was mainly considered as an intracellular protein involved in Se metabolism and redox control. Our data indicate that SELENBP1 constitutes a circulating biomarker for cardiac events categorizing patients with suspected ACS at first medical contact into high-risk or low-risk for MACE and death, independent from and complimentary to current biomarkers.