Background: Acute Kidney Injury (AKI) is a frequent, dangerous
complication in patients undergoing cardiopulmonary bypass (CPB) with oxidative
stress playing a crucial role. In this pilot study we evaluated the possible role
of the selenoprotein-p1 (SEPP1), a circulating, anti-oxidant selenium
transporter, as a predictive biomarker of AKI in this population setting.
Methods: Circulating SEPP1 was measured in the blood of 45 patients
before surgery and at 4 h, 8 h and 12 h after CPB by Enzyme-Linked Immunosorbent
Assay (ELISA). Results: SEPP1 increased from 69 [IQR 39–85] to 3263 [IQR
1886.2–5042.7] ng/mL (p for trend 0.0001). AKI occurred in 26.7% of
patients. In these individuals, an earlier and more prominent increase in SEPP1
was observed at 4 h and 8 h, as compared with those not experiencing AKI
(difference between trends p 0.0001). Logistic regression analyses
evidenced 4 h and 8 h SEPP1 as significantly associated with AKI (OR 1.035; 95% CI
1.002–1.068; p = 0.03 and 1.011; 95% CI 1.002–1.021; p =
0.02, respectively). ROC analyses displayed a remarkable discriminatory capacity
of early SEPP1 measurements in identifying AKI (AUCs ranging from 0.682 to 0.854;
p from 0.04 to 0.0001). In addition, 12 h-SEPP1 showed diagnostic
capacity to identify patients reaching a secondary composite endpoint including
major adverse kidney events (MAKEs). Conclusions: Findings from this
pilot, exploratory study suggest that early SEPP1 measurement after CPB may hold
great potential for improving renal risk stratification in cardiac surgery
patients. Further studies in wider and more heterogeneous cohorts are needed to
generalize these findings and to evaluate a possible applicability in daily
practice.