Expression of B2 Receptor on Circulating CD34-Positive Cells and Outcomes of Myocardial Infarction

Abstract

Background: Bradykinin B2 receptor (B2R) is a widely expressed cell surface receptor. The relationship between B2R expression on circulating CD34+ cells and prognosis of myocardial infarction remains unknown. Methods: We analyzed the expression of B2R on circulating CD34-positive cells and plasma VEGF concentration in 174 myocardial infarction patients. All involved patients were divided into two groups: high B2R group and low B2R group according to the median B2R expression percentage. 48 months of follow-up was performed. The endpoints were heart failure and revascularization. Results: The plasma level of VEGF in the low B2R group is 67 ± 12 pg/mL, whereas the high B2R group has significantly elevated VEGF levels of 145 ± 27 pg/mL (P < 0.001). The concentration of VEGF has correlated with expression of B2R (r = 0.574, P < 0.001). During the 48 months of follow-up, low expression of B2 receptor on circulating CD34-positive cells indicates the high incidence of heart failure (hazard ratio: 2.247; 95% confidence interval: 1.110-4.547; P = 0.024) and revascularization (hazard ratio: 2.335; 95% confidence interval: 1.075-5.074; P = 0.032). Kaplan-Meier survival analysis showed that the cumulative hazard of heart failure (P = 0.014) and revascularization (P = 0.032) has significant differences between low B2R and high B2R. Conclusion: Low expression of B2R on circulating progenitor cells indicated the poor outcomes of myocardial infarction.