Cardiovascular diseases are the leading cause of death all over the world. Various biomarkers are available to prognose and diagnose cardiovascular diseases. The aims of this thesis are to introduce a novel cardiac marker, myeloperoxidase (MPO), for prognosis of future cardiovascular diseases; to develop reliable immunoassays, namely enzyme-linked immunosorbent assay (ELISA) and a lateral-flow assay, for MPO measurements; and also to develop a lateral-flow assay for a gold standard cardiac marker, cardiac troponin I (cTnI), and a combined lateral-flow assay for an early cardiac marker, heart-type fatty acid-binding protein (H-FABP), together with cTnI for diagnosis of acute myocardial infarction (AMI)....[ Read more ]

Cardiovascular diseases are the leading cause of death all over the world. Various biomarkers are available to prognose and diagnose cardiovascular diseases. The aims of this thesis are to introduce a novel cardiac marker, myeloperoxidase (MPO), for prognosis of future cardiovascular diseases; to develop reliable immunoassays, namely enzyme-linked immunosorbent assay (ELISA) and a lateral-flow assay, for MPO measurements; and also to develop a lateral-flow assay for a gold standard cardiac marker, cardiac troponin I (cTnI), and a combined lateral-flow assay for an early cardiac marker, heart-type fatty acid-binding protein (H-FABP), together with cTnI for diagnosis of acute myocardial infarction (AMI).

CardioCare MPO ELISA kit for the detection of MPO in plasma samples has been successfully developed. One hundred and four plasma samples were evaluated using the CardioCare MPO ELISA and a commercially available ELISA. The correlation was found to be y= 0.9167x – 10.136 (R² = 0.9211). In order to have more accurate result, citrate- and EDTA-plasma should be used. Fifty-three acute coronary syndrome (ACS) patients, ninety-three high cardiac risk patients and twenty normal healthy subjects were tested by the CardioCare MPO ELISA, and the mean values were 124.9 ± 121.8 µg/L, 78.6 ± 42.5 μg/L and 44.9 ± 18.4 μg/L respectively (P < 0.001).

A newly developed CardioCare MPO “Barcode-style” lateral-flow test can show one to three lines depending on different MPO concentrations. Heart attack and stroke risk can be assessed by simply counting the number of test lines. The result gives visible signals that can be assessed as “LOW RISK”, “MODERATE RISK” or “HIGH RISK” without any expensive reading device. Medical doctors can semi-quantify the extent of the risk and prescribe stroke or heart attack-preventing therapy.

A rapid and quantitative lateral-flow assay, so-called CardioAlert cTnI, for detection of cTnI in serum, plasma and blood samples has been successfully developed. Also, a rapid and quantitative lateral-flow assay, so-called CardioDetect Plus, for detection of cTnI and H-FABP in serum, plasma and blood samples has been successfully developed. Both assays give results within 20 minutes. The correlation between a commercial ELISA and the CardioAlert cTnI test was found to be y = 0.8029 + 3.9834 (R² = 0.9727) by using 20 serum samples. The correlations between a commercial ELISA and the CardioDetect Plus test, were found to be y = 0.8029 + 3.9834 (R² = 0.9727) for cTnI by using 20 serum samples and to be y = 0.9718x + 4.0174 (R² = 0.9593) for H-FABP by using 31 serum samples. With the combination of early and late cardiac biomarkers, the diagnosis of AMI can become much accurate and convenient.