Fig. 3

Effects of cardiopulmonary bypass on the inflammatory infiltration and number of c-kit⁺CD45⁻ cells in the myocardial biopsies. Cardiopulmonary bypass significantly decreased the leucocyte infiltration in newborns (n = 4) but not in children (a) (n = 7) evaluated by immunostaining for leukocyte common antigen CD45. The percentage of eosinophils was also reduced in newborns after CPB (d). In contrast, cardiopulmonary bypass increased the number of c-kit⁺CD45⁻ cells in newborns and decreased their number in children (g, i). There was no statistical difference in the percentage of CD45⁺cells (b), eosinophils (e) and in the number of c-kit⁺CD45⁻ cells (h) in the biopsies from the atrium and ventricle of children (n = 3). Representative sections from the atrium of a newborn before and after cardiopulmonary bypass demonstrating co-immunostaining for common leucocyte marker CD45 (red) and cardiomyocyte marker alpha-sarcomeric actin (green) (c). Nuclei are stained blue by DAPI. Bars = 10 µm. Representative sections from the atrium of a newborn before and after cardiopulmonary bypass demonstrating eosinophils marked by arrowheads. Hematoxylin–eosin staining (f). Bars = 10 µm. A c-kit⁺CD45⁻ cell in the atrium of a newborn co-immunostaining for c-kit⁺ CD117 (red) and cardiomyocyte marker alpha-sarcomeric actin (green) (c). Nuclei are stained blue by DAPI. Bar = 10 µm