18F-FDG Uptake Assessed by PET/CT in Abdominal Aortic Aneurysms Is Associated with Cellular and Molecular Alterations Prefacing Wall Deterioration and Rupture

A. Courtois, B. V. Nusgens, R. Hustinx, G. Namur, P. Gomez, J. Somja, J.-O. Defraigne, P. Delvenne, J.-B. Michel, A. C. Colige, N. Sakalihasan
2013 Journal of Nuclear Medicine  
Rupture of abdominal aortic aneurysms (AAAs) leads to a significant morbidity and mortality in aging populations, and its prediction would be most beneficial to public health. Spots positive for uptake of 18 F-FDG detected by PET are found in 12% of AAA patients (PET1), who are most often symptomatic and at high rupture risk. Comparing the 18 F-FDG-positive site with a negative site from the same aneurysm and with samples collected from AAA patients with no 18 F-FDG uptake should allow the
more » ... ould allow the discrimination of biologic alterations that would help in identifying markers predictive of rupture. Methods: Biopsies of the AAA wall were obtained from patients with no 18 F-FDG uptake (PET0, n 5 10) and from PET1 patients (n 5 8), both at the site positive for uptake and at a distant negative site of the aneurysmal wall. Samples were analyzed by immunohistochemistry, quantitative real-time polymerase chain reaction, and zymography. Results: The sites of the aneurysmal wall with a positive 18 F-FDG uptake were characterized by a strikingly increased number of adventitial inflammatory cells, highly proliferative, and by a drastic reduction of smooth muscle cells (SMCs) in the media as compared with their negative counterpart and with the PET0 wall. The expression of a series of genes involved in the maintenance and remodeling of the wall was significantly modified in the negative sites of PET1, compared with the PET0 wall, suggesting a systemic alteration of the aneurysmal wall. Furthermore, a striking increase of several matrix metalloproteinases (MMPs), notably the MMP1 and MMP13 collagenases, was observed in the positive sites, mainly in the adventitia. Moreover, PET1 patients were characterized by a higher circulating C-reactive protein. Conclusion: Positive 18 F-FDG uptake in the aneurysmal wall is associated with an active inflammatory process characterized by a dense infiltrate of proliferating leukocytes in the adventitia and an increased circulating C-reactive protein. Moreover, a loss of SMC in the media and alterations of the expression of genes involved in the remodeling of adventitia and collagen degradation potentially participate in the weakening of the aneurysmal wall preceding rupture. Rupture Associated with Cellular and Molecular Alterations Prefacing Wall Deterioration and F-FDG Uptake Assessed by PET/CT in Abdominal Aortic Aneurysms Is 18 http://jnm.snmjournals.org/content/54/10/1740 This article and updated information are available at: http://jnm.snmjournals.org/site/subscriptions/online.xhtml Information about subscriptions to JNM can be found at: http://jnm.snmjournals.org/site/misc/permission.xhtml
doi:10.2967/jnumed.112.115873 pmid:24009278 fatcat:hw6f7zah5fbj5nwluwlj45poua