title: Correlation of bacterial coinfection versus matrix metalloproteinase 9 and tissue inhibitor of metalloproteinase 1 expression in aortic aneurysm and atherosclerosis.
abstract: BACKGROUND
  We searched for any relationship between Chlamydophila pneumoniae, Mycoplasma pneumoniae, matrix metalloproteinase 9 (MMP-9), and tissue inhibitor of metalloproteinase 1 (TIMP-1) in aneurysmatic atherosclerotic lesions, and whether this relationship differed from that in atherosclerotic nonaneurysmatic lesions.
  
  
  METHODS
  Twenty-eight tissue samples paired by age and sex were grouped as follows: group 1 included 14 nonaneurysmal atherosclerotic fragments obtained from abdominal aortas collected from necropsies; group 2 included 14 aneurysmatic atherosclerotic aortic fragments obtained from patients during corrective surgery. Immunohistochemistry reactions were evaluated for C pneumoniae, M pneumoniae, MMP-9, and TIMP-1 antigens. Both groups were compared using the Mann-Whitney test, and the correlations among variables were obtained using the Spearman correlation test. P ≤ 0.05 was considered statistically significant.
  
  
  RESULTS
  C pneumoniae and M pneumoniae antigens were detected in 100% of cases. A higher amount of C pneumoniae (P = 0.005), M pneumoniae (P = 0.002), and MMP-9 (P = 0.021) was found in adventitia of group 2 with aneurysm. A positive correlation was found in the aneurysm group, as follows: intima C pneumoniae versus adventitia thickness (r = 0.70; P = 0.01), media C pneumoniae versus adventitia C pneumoniae (r = 0.75; P = 0.002), intima C pneumoniae versus media C pneumoniae (r = 0.8; P = 0.00), and adventitia C pneumoniae versus intima M pneumoniae (r = 0.54; P = 0.05); negative correlations were as follows: adventitia thickness and adventitia M pneumoniae (r = -0.65; P = 0.01), media MMP-9 and media thickness (r = -0.55; P = 0.04), TIMP-1 media versus adventitia C pneumoniae (r = -0.86; P = 0.00), and TIMP-1 media versus M pneumoniae intima (r = -0.67; P = 0.03). Nonaneurysmal atherosclerotic group 1 results are as follows: adventitia C pneumoniae versus TIMP-1 media (r = 0.75; P = 0.01) and media C pneumoniae and adventitia C pneumoniae (r = 0.59; P = 0.03).
  
  
  CONCLUSIONS
  The present work favors a role for coinfection of both M pneumoniae and C pneumoniae in the development of aortic atherosclerotic aneurysm, with increased adventitial inflammation, inhibition of TIMP-1 activity, and increased collagen degradation.
authors.affiliation: Inflammation Laboratory, Heart Institute of Clinical Hospital, Medical School, University of São Paulo, São Paulo, Brazil.
authors.forename: Alessandra
authors.initials: A
authors.lastname: Roggério
authors.forename: Nádia Vieira
authors.initials: NV
authors.lastname: Sambiase
authors.forename: Suely A P
authors.initials: SA
authors.lastname: Palomino
authors.forename: Maria Alice Pedreira
authors.initials: MA
authors.lastname: de Castro
authors.forename: Erasmo Simão
authors.initials: ES
authors.lastname: da Silva
authors.forename: Noedir G
authors.initials: NG
authors.lastname: Stolf
authors.forename: Maria
authors.initials: M
authors.lastname: de Lourdes Higuchi
mesh_terms: D063194:Adventitia / Q000201:enzymology / Q000382:microbiology; D000368:Aged; D000785:Aneurysm, Infected / Q000175:diagnosis / Q000201:enzymology* / Q000382:microbiology / Q000601:surgery; D001011:Aorta / Q000201:enzymology* / Q000382:microbiology / Q000473:pathology; D001014:Aortic Aneurysm / Q000175:diagnosis / Q000201:enzymology* / Q000382:microbiology / Q000601:surgery; D050197:Atherosclerosis / Q000175:diagnosis / Q000201:enzymology*; D023521:Chlamydophila Infections / Q000175:diagnosis / Q000201:enzymology* / Q000382:microbiology / Q000601:surgery; D016993:Chlamydophila pneumoniae / Q000302:isolation & purification; D060085:Coinfection; D004108:Dilatation, Pathologic; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000032:analysis*; D008875:Middle Aged; D009177:Mycoplasma pneumoniae / Q000302:isolation & purification; D011019:Pneumonia, Mycoplasma / Q000175:diagnosis / Q000201:enzymology* / Q000382:microbiology / Q000601:surgery; D019715:Tissue Inhibitor of Metalloproteinase-1 / Q000032:analysis*
chemical_list: C560822:TIMP1 protein, human; D019715:Tissue Inhibitor of Metalloproteinase-1; C579270:MMP9 protein, human; D020780:Matrix Metalloproteinase 9