Differential levels of circulating progenitor cells in acute coronary syndrome patients with a first event versus patients with recurring events

OBJECTIVE: Pathophysiology of acute coronary syndromes in patients presenting with a first cardiac event (FCE) can be different from patients with a recurring cardiac event (RCE). We assessed inflammatory activation and circulating progenitor cells' (CPC) mobilisation in patients with a FCE versus those with RCE. METHODS: We recruited 41 patients: 18 with FCE and 23 with RCE. Peripheral blood samples were drawn at baseline and at 20 days to measure high sensitivity C-reactive protein (CRP) and to assess CD34+/133+ CPC and CD34+/KDR+ CPC by flow cytometry. RESULTS: CD34+/133+ cells (% number of cells per total number of cytometric events) were similar at baseline, being 0.25% (0.17-0.42%) in the FCE vs 0.23% (0.11-0.43%) in the RCE group, and increased at follow-up only in the FCE group to 0.41% (0.22-0.64%), while in the RCE group they were 0.27% (0.11-0.36%) (p=0.009 for the interaction, p=0.07 for the main effect of time). CD34+/KDR+ cells were similar at baseline in the two groups, did not significantly increase over time (p=0.2), and no differential effect of FCE vs RCE over time was seen (p=0.38). CRP levels, similar at baseline, were consistently reduced at 20 days after ACS (p=0.001), with no differential effect of FCE vs RCE pts (p=0.74). Variation from baseline to follow-up for both CD34+/133+ and CD34+/KDR+ did not correlate with either baseline CRP or delta CRP. CONCLUSIONS: Our data demonstrate a differential CPC mobilization behavior for FCE patients compared to RCE ones, independent of inflammatory activation.