Development of a Point-of-Care Test Based on Selenium Nanoparticles for Heart-Type Fatty Acid-Binding Proteins in Human Plasma and Blood.

Purpose: A rapid, convenient, cost-effective in-home test method for identifying heart-type fatty acid-binding protein (H-FABP) in plasma and blood by a lateral-flow immunoassay (LFIA) based on selenium nanoparticles (SeNPs) was developed. Methods: SeNPs were synthesized by using L-ascorbic acid to reduce seleninic acid at room temperature and conjugated with an anti-H-FABP monoclonal antibody. The limit of detection, specificity, and stability were measured, and clinical samples were analyzed. Results: The SeNPs were spherical with a diameter of 39.48 ± 3.72 nm and were conjugated successfully with an anti-H-FABP antibody, resulting in a total diameter of 46.52 ± 2.95 nm. The kit was designed for the determination of H-FABP in plasma specimens and whole blood specimens. The limit of detection was 1 ng/mL in plasma and blood, and the results could be determined within 10 min. No cross-reaction occurred with cardiac troponin I, creatine kinase-MB or myoglobin. The kits were stored at 40 °C for up to 30 days without significant loss of activity. The sensitivity was determined to be 100%, the specificity 96.67%, and the overall coincidence rate 97.83%. Conclusion: This SeNP assay kit can conveniently, rapidly, and sensitively detect H-FABP in plasma or blood with a readout of a simple color change visible to the naked eye with no special device, and can be used as an auxiliary means for the early screening of AMI. Clinical Trial Registration: Plasma and blood samples were used under approval from the Experimental Animal Ethics committee of the Joint National Laboratory for Antibody Drug Engineering, Henan University. The clinical trial registration number was HUSOM-2019-047.

Rapid detection of human heart-type fatty acid-binding protein in human plasma and blood using a colloidal gold-based lateral flow immunoassay.

The incidence of acute myocardial infarction (AMI) is currently increasing. Early detection is important for the treatment and prognosis of patients with AMI. Heart-type fatty acid-binding protein (H-FABP) may be used as an early marker of AMI due to its high sensitivity, specificity and prognostic value. Therefore, in the present study, H-FABP was used as a biomarker in a double-antibody sandwich method and colloidal gold-based lateral flow immunoassay to develop a rapid detection kit for H-FABP with a processing time of only 5 min. The sensitivity of the kit in plasma and whole blood was 1 ng/ml and this method had good specificity, exhibiting no cross-reaction with cardiac troponin I, myoglobin or creatine kinase-Mb. The kits had good shelf life and stability, as they were able to be stored at 40˚C for 30 days. A total of 12 clinical samples were collected for detection and the coincidence rate with the ELISA method was up to 91.67%. Therefore, the present study provided a simple, rapid and economical early-detection in-home testing kit.

Blocking the death checkpoint protein TRAIL improves cardiac function after myocardial infarction in monkeys, pigs, and rats.

Myocardial infarction (MI) is a leading cause of death worldwide for which there is no cure. Although cardiac cell death is a well-recognized pathological mechanism of MI, therapeutic blockade of cell death to treat MI is not straightforward. Death receptor 5 (DR5) and its ligand TRAIL [tumor necrosis factor (TNF)-related apoptosis-inducing ligand] are up-regulated in MI, but their roles in pathological remodeling are unknown. Here, we report that blocking TRAIL with a soluble DR5 immunoglobulin fusion protein diminished MI by preventing cardiac cell death and inflammation in rats, pigs, and monkeys. Mechanistically, TRAIL induced the death of cardiomyocytes and recruited and activated leukocytes, directly and indirectly causing cardiac injury. Transcriptome profiling revealed increased expression of inflammatory cytokines in infarcted heart tissue, which was markedly reduced by TRAIL blockade. Together, our findings indicate that TRAIL mediates MI directly by targeting cardiomyocytes and indirectly by affecting myeloid cells, supporting TRAIL blockade as a potential therapeutic strategy for treating MI.