Proteomic Analysis of Intraluminal Thrombus Highlights Complement Activation in Human Abdominal Aortic Aneurysms

Objective—To identify proteins related to intraluminal thrombus biological activities that could help to find novel pathological mechanisms and therapeutic targets for human abdominal aortic aneurysm (AAA). Approach and Results—Tissue-conditioned media from patients with AAA were analyzed by a mass spectrometry–based strategy using liquid chromatography coupled to tandem mass spectrometry. Global pathway analysis by Ingenuity software highlighted the presence of several circulating proteins, among them were proteins from the complement system. Complement C3 concentration and activation were assessed in plasma from AAA patients (small AAA, AAA diameter=3–5 cm and large AAA, AAA diameter >5 cm), showing decreased C3 levels and activation in large AAA patients. No association of a combination of single-nucleotide polymorphisms in complement genes between large and small AAA patients was observed. Intense extracellular C3 inmunostaining, along with C9, was observed in AAA thrombus. Analysis of C3 in AAA tissu...