Characterization of neutrophil extracellular traps (NETs) in human AAA samples.

<p>The presence of NETs in AAA intral-luminal thrombus (ILT) and in aneurysmal wall was demonstrated by co-immunostaining of histone H1, citrullinated histone H4 (cit-H4) and elastase. Nuclei were stained with DAPI (100 ng/ml, 15 minutes). (A) Immunostaining for histone H1 (green) showing destructured nuclei in the luminal (lum) part of ILT as well as in the adventitia (Adv). (B) Immunostaining for cit-H4 and elastase demonstrates specific neutrophil activation prior to DNA expulsion. (C) The release of cit-H4 was analyzed by western blot in the conditioned medium from the different layers of ILT (luminal: Lum, intermediate: Int and abluminal: Abl) and of the remaining aortic wall (media: Med and adventitia: Adv). (D) Terminal-transferase dUTP Nick End Labelling (TUNEL) staining in the luminal part of ILT (green). TUNEL-positive cells are indicated by grey arrowheads. Extracellular nucleosomes (NETs) are indicated by white arrowheads. Merged images were obtained using Archimed software.