Development of immunoassays for quantitative detection of a novel cardiovascular risk assessment biomarker : lipocalin-2

Abstract

Cardiovascular diseases (CVD) are the major causes of mortality and morbidity in general population. Conventional markers, like low-density lipoprotein (LDL) and C-reactive protein (CRP) are used for prognosis of CVD. However, the ability of those factors to identify such patients is limited and the clinical values of them are still questionable. Recently, lipocalin-2 (LCN2), a 25 kDa secretory glycoprotein, has been regarded as a novel biomarker for cardiovascular risk assessment. It is involved in the pathogenesis of obesity and CVD by inflammatory process. There is even an evidence showing that LCN2 is a superior independent biomarker compared to CRP for CVD death prediction. A simple with high detection range enzyme-linked immunosorbent assay (ELISA) was developed for quantitative detection of LCN2 in serum, plasma and urine. The detection limit and functional sensitivity are 0.20 and 0.39 μg/L, respectively. A rapid, portable and user-friendly point-of-care lateral-flow immunoassay was also developed for quantification of LCN2 in whole blood, serum and plasma. The detection limit and functional sensitivity are 1.5 and 2.0 μg/L, respectively. In order to increase the prognostic performance of CRP, a dual-biomarker lateral-flow immunoassay was invented for simultaneous quantification of LCN2 and CRP within 15 min. The prognostic performance of LCN2 was evaluated with obese/diabetic patients, patients with acute coronary syndrome (ACS) and the control group. Based on the results of ACS patients and the control group, the LCN2 cut-off value found was 31 μg/L using the in-house ELISA and 33 μg/L using the developed lateral-flow immunoassay. The diagnostic sensitivity was 0.75. It was also found that obese/diabetic patients had higher serum LCN2 concentrations than health subjects (P < 0.05). After combining both LCN2 and CRP, the diagnostic sensitivity of LCN2 increased of from 0.75 to 0.90. Therefore, it is concluded that LCN2 can be applied for risk stratification of CVD.

Date of Award	2013
Original language	English
Awarding Institution	The Hong Kong University of Science and Technology