sMICA as novel and early predictors for acute myocardial infarction

Background and aims: MHC class I polypeptide-related chain A (MICA) molecule is induced in response to viral infection, various types of stress, such as endoplasmic reticulum stress, and ischemia or/and reperfusion, by which MICA was shed from the cell surface into the extracellular domain, generating a soluble form (sMICA). In the present study, we designed to investigate the serum sMICA level in patients with AMI and determine whether sMICA could be an early biomarker for diagnosis of AMI. Methods: There were 103 patients who presented with first-time AMI that was assessed after the incident. The control group consisted of 103 healthy volunteers. Serum levels of sMICA and Troponin T were detected by the specific ELISA kits. Results: Serum levels of sMICA reach the peaks [(1.34 +/- .18 and 1.72 +/- .20)n/l] at 6-12 h and serum levels of cTnT reach the peaks [(1.16 +/- .28 and 1.14 +/- .34)n/l] at 12-24 h. Both of them were significantly higher than the healthy controls [(.168 +/- .014)n/l, p = .000] for sMICA and [(.13 +/- .06)n/l, p = .000] for Troponin T (cTnT). sMICA is more sensitive in the early diagnosis of AMI than cTnT. The combined ROC analysis revealed an AUC value of .78 (95 % CI.69-.83) in discriminating AMI patients from healthy controls. Conclusions: We have detected high levels of sMICA in patients with AMI. Elevated serum sMICA may be a novel biomarker for the early detection of myocardial injury in humans.