The aim of this study was to analyze modifications in the plasma protein map during an acute coronary syndrome (ACS) using proteomics. Proteomics is a new technology that allows the detection and identification of several proteins at a given time in a sample. Plasma from 19 patients, 11 with acute myocardial infarction (AMI) and 8 with unstable angina (UA), was investigated. The control group included nine age-matched volunteers. In two-dimensional electrophoresis using a pH range of 4 to 7, constant differences were found in at least four different areas within the plasma protein map. In area 1, we identified the presence of seven alpha(1)-antitrypsin (AAT) isoforms in plasma from control subjects. alpha(1)-antitrypsin isoform 1 was undetectable in plasma from UA and AMI patients. The AAT isoforms 5, 6, and 7 were reduced in plasma from AMI patients when compared with UA patients. Three fibrinogen gamma chain isoforms were identified in area 2. Fibrinogen gamma chain isoforms 1 and 2 were increased in AMI patients with respect to UA patients. Five apolipoprotein A-I isoforms were identified in area 3. All of them were reduced in plasma from AMI patients with respect to UA patients. In area 4, the gamma-immunoglobulin heavy chains were detected and were found increased in plasma from ACS patients. Plasma proteomic analysis makes it possible to develop a map of the protein isoforms that are expressed in plasma during an ACS.
