RESUMO
BACKGROUND: CD163 is a scavenger receptor for the uptake of haptoglobin-hemoglobin (Hpt-Hb) complexes. The Hpt-Hb complexes are being formed in the plaque in response to intraplaque hemorrhage, a hallmark of atherosclerotic plaque instability. We therefore investigated whether soluble CD163 (sCD163) was elevated in patients with an acute coronary syndrome. METHODS: All subjects presenting with chest pain suggestive of myocardial ischemia referred to either the emergency department or the coronary care unit were included in a prospective follow-up study. Plasma was collected and frozen at -80 degrees C until assayed. sCD163 was measured using a commercially available Elisa assay. RESULTS: Of 526 included chest pain patients, the final diagnosis was non-cardiac chest pain in 244 (46%) patients, non-STEMI in 67 (13%), and STEMI in 215 (41%). The non-STEMI patients were older, used more medication, had undergone more often coronary interventions, but did not differ with respect to risk factors, except for a higher incidence in dyslipidemia. Unexpectedly, sCD163 did not differentiate between patients with non-STEMI or STEMI and the non-cardiac chest pain patients (2.09+/-0.76 versus 2.24+/-0.86). CONCLUSION: Although ACS is characterized by intraplaque hemorrhage, the amount of intraplaque Hb release seems not to be substantial enough to result in a measurable difference in sCD163.