| Acute myocardial infarction (AMI) is a deadly disease to threat human life world wide, and it is crucial to save the threaten lives with early detection of AMI. The release of myocardial proteins from injured cardiac tissue into blood plasma is an important diagnostic parameter for the exclusion or confirmation of AMI. The activities of myocardial markers traditionally assessed by cardiac enzymes such as creatine kinase isoenzyme MB (CK-MB), tropininT, tropinin I, and myoglobin. Myoglobin (MYO) is introduced to detect the early onset of AMI, whereas the other proteins are detected at least four hours after the symptom onset, but its usefulness is limited by its low specificity. Recently, another cardiac protein, heart-type fatty acid-binding protein (H-FABP) has been proposed as an early plasma marker for AMI. H-FABP is a low molecular weight (15KD) cytoplasmic protein and that is abundant in the cytoplasm of myocardial cells. Due to its small siç€, it is released into plasma in significant amounts \vithin 1.3~3h of the onset of AMI. Some clinical studies have shown that H-FABP seems better than MYO for the early detection of AMI, especially in first 3h after AMI. In the present study, we assessed the characteristics of H-FABP by the enzyme-linked immunosorgent assay (ELISA) and discussed its usefulness of early detection of AMI for the firsttime in our country.Materials and methods: The study included 126 healthy individuals (74 man and 52 woman, the normal group), 41 the è¯D patients with angina pectoris (29 man and 12 vvoman, è¯D group), and the AMI patients (32 man and 21 woman, AMI group). The AMI group was further divided into reperfused group and non-reperfused group according to their treatment. The blood samples were taken upon admission to the hospital for normal group and è¯D group. For AMI group, the blood samples were obtained at the time of admission, 2h, 4h, 6h, 8h, lOh, 12h, 14h, 16h, 18h, 20h, 22h, 24h, 48h, and 72h after the onset of symptoms. The activities of CK-MB, MYO, H-FABP, cTnl in plasma then were measured and compared among them.Results: In plasma from healthy individuals H-FABP amounted to 3.79?.52 M g/L, MYO 46.34?5.67 ug/L, cTnl 2.66?.48 ug/L and CK-MB 5.76?.81 U/L. The upper limit of the reference interval (discriminator value to rule in AMI) calculated as mean value +2SD thus amounting for H-FABP, CK-MB, MYO and cTnl was 10.83 Mg /L, 15.36 U/L, 77.68 p.g/L and 7.62 ug/L.The dynamic changes of plasma concentrations of those markers after AMI and the normalized raios expressed relative to the respective discriminator values vvere analysed. H-FABP increased sharply after AMI within 2 hours, andpeaking at 6.17?.40h in the reperfused group, and 7.87?.5h in the non -reperfused group. The peaking time seemed earlier in the reperfused group than that of the non-reperfused group for 1.7 hours. The concentration of MYO showed a similar time of course of changes, sharply increased after AMI within 2 hours, peaking at 6.51?1.40h in reperfused group and 7.77?.03h in non-reperfused group. The peaking time seemed earlier in reperfused group than that in non-reperfused for 1.26 hours. Release of H-FABP and MYO seemed to occur and be completed much earlier than that of CK-MB and cTnl.ROC curves were used to assess the performance of H-FABP and the other markers within 2 hours and 4 hours after symptom onset. The area under the ROC curve at 2 hours of H-FABP was 0.928 (95%CI 0.893-0.963), MYO was 0.821(95%CI 0.739-0.904), CK-MB was 0.687 (95%CI 0.617 -0.75), cTnl was 0.559 (95%CI 0.472-0.646). The area under the ROC curve at 4 hours of H-FABP was 0.951(95%CI 0.918-0.984), and that of MYO was 0.880(95%CI 0.805-0.954), CK-MB was 0.797 (95%CI 0.73-0.864), cTnl was 0.759 (95%CI 0.674-0.844). The areas under the ROC curves were H-FABP > MYO > CK-MB > cTnl both at 2 hours and 4 hours after symptom onset.Conclusion: Conclusions can be made from this work as the following:1. The plasma concentration of H-FABP in healthy individuals was 3.79+3.52 n g/...
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