title: Differential protein expression in serum of abdominal aortic aneurysm patients - a proteomic approach.
abstract: OBJECTIVE
  The aim of the study is to investigate the differential expression of proteins in serum of abdominal aortic aneurysm (AAA) patients in relation to aneurysm size (D(max)) and progression.
  
  
  METHODS
  Two-dimensional differential in-gel electrophoresis (2D-DIGE) together with tandem mass spectrometry (MS/MS) was used to analyse the serum proteome from patients with small (D(max) 30-54 mm) AAA, either stable (increase D(max) <5 mm year⁻¹; n = 8) or progressive (increase D(max) ≥5 mm year⁻¹; n = 8), and large (D(max) ≥ 55 mm; n = 8) AAA. The identified proteins were quantitatively validated in a larger population (n = 80).
  
  
  RESULTS
  Several proteins were differentially expressed in serum of small stable, small progressive and large AAA. Three validated proteins (immunoglobulin G (IgG), α1-antitrypsin (α1-AT) and Factor XII activity) showed strong correlation with D(max). Size combined with either Factor XII activity or α1-antitrypsin had minimal effect on the prognostic value in predicting aneurysm progression compared with size alone (area under the curve (AUC), 0.85; 95% confidence interval (CI), 0.73-0.97; p < 0.001 and AUC, 0.85; 95% CI, 0.72-0.98; p < 0.001 vs. AUC, 0.83; 95% CI, 0.71-0.96; p < 0.001, respectively).
  
  
  CONCLUSIONS
  The present study indicates that both Factor XII and α1-antitrypsin are found in increased amounts in the serum of patients with expanding AAA. However, combination of either Factor XII or α1-antitrypsin with aneurysm diameter had little effect on prediction of aneurysm progression versus diameter alone.
authors.affiliation: Department of Clinical Chemistry, Maastricht University Medical Centre, Maastricht, The Netherlands.
authors.forename: B
authors.initials: B
authors.lastname: Pulinx
authors.forename: F A M V I
authors.initials: FA
authors.lastname: Hellenthal
authors.forename: K
authors.initials: K
authors.lastname: Hamulyák
authors.forename: M P
authors.initials: MP
authors.lastname: van Dieijen-Visser
authors.forename: G W H
authors.initials: GW
authors.lastname: Schurink
authors.forename: W K W H
authors.initials: WK
authors.lastname: Wodzig
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D017544:Aortic Aneurysm, Abdominal / Q000097:blood* / Q000235:genetics / Q000473:pathology*; D015331:Cohort Studies; D005174:Factor XII / Q000378:metabolism; D005260:Female; D006801:Humans; D007074:Immunoglobulin G / Q000097:blood; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D020543:Proteome; D053719:Tandem Mass Spectrometry; D057825:Two-Dimensional Difference Gel Electrophoresis; D000515:alpha 1-Antitrypsin / Q000097:blood
chemical_list: D007074:Immunoglobulin G; D020543:Proteome; D000515:alpha 1-Antitrypsin; D005174:Factor XII