Detection of urine cofilin-1 from patients hospitalized in the intensive care unit using the metal-enhanced fluorescence technique

Ischemic shock and acute kidney injury (AKI) are the primary causes of high mortality in the intensive care unit (ICU) patients. In a rat model, ischemia is able to disrupt the actin cytoskeleton of proximal tubule cells. This effect is associated with the expression and excretion of actin depolymerizing factor (ADF)/cofilin. However, the human evidence of ADF/cofilin excreted in ICU patients with ischemic shock and/or AKI remains to be addressed. Here we developed a 96-well high-throughput, localized surface plasmon-coupled fluorescence biosensor (HT-LSPCFB) combining a sandwich immunoassay to measure the urine cofilin-1 in 57 ICU patients and 8 healthy controls. A linear relationship between 1 and 105 pg/mL of human cofilin-1 recombinant protein was determined (R2 = 0.9845) in this study. The highest normalized cofilin-1 levels obtained in the ICU patients and healthy adults were 1.985 and 0.726, respectively. The mean normalized cofilin-1 level of total ICU patients (0.7403) was also significantly higher than that of healthy adults (0.4759) (p = 0.0052). An examination of the receiver operating characteristic (ROC) curve and area under curve (AUC) showed that cofilin-1 is acceptable for assessing the ICU patients (AUC = 0.775) and shock (AUC = 0.713), but not for AKI (AUC = 0.681). Therefore, the HT-LSPCFB is suitable for detecting the urine cofilin-1 which potentially becomes a prognostic factor for ICU patients with shock.