Adventitial adipogenic degeneration is an unidentified contributor to aortic wall weakening in the abdominal aortic aneurysm

Doderer, Stefan A.; Gäbel, Gabor; Kokje, Vivienne B. C.; Northoff, Bernd H.; Holdt, Lesca M.; Hamming, Jaap F. und Lindeman, Jan H. N. (2018): Adventitial adipogenic degeneration is an unidentified contributor to aortic wall weakening in the abdominal aortic aneurysm. In: Journal of Vascular Surgery, Bd. 67, Nr. 6: S. 1891-1900

Abstract

Objective: The processes driving human abdominal aortic aneurysm (AAA) progression are not fully understood. Although antiinflammatory and proteolytic strategies effectively quench aneurysm progression in preclinical models, so far all clinical interventions failed. These observations hint at an incomplete understanding of the processes involved in AAA progression and rupture. Interestingly, strong clinical and molecular associations exist between popliteal artery aneurysms (PAAs) and AAAs;however, PAA5 have an extremely low propensity to rupture. We thus reasoned that differences between these aneurysms may provide clues toward (auxiliary) processes involved in AAA-related wall debilitation. A better understanding of the pathophysiologic processes driving AAA growth can contribute to pharmaceutical treatments in the future. Methods: Aneurysmal wall samples were collected during open elective and emergency repair. Control perirenal aorta was obtained during kidney transplantation, and reference popliteal tissue obtained from the anatomy department. This study incorporates various techniques including (immuno)histochemistry, Western Blot, quantitative polymerase chain reaction, microarray, and cell culture. Results: Histologic evaluation of AAAs, PAA5, and control aorta shows extensive medial (PAA) and transmural fibrosis (AAA), and reveals abundant adventitial adipocytes aggregates as an exclusive phenomenon of AAAs (P <.001). Quantitative polymerase chain reaction, immunohistochemistry, Western blotting, and microarray analysis showed enrichment of adipogenic mediators (C/EBP family P =.027;KLF5 P <.000;and peroxisome proliferator activated receptor-y, P =.032) in AAA tissue. In vitro differentiation tests indicated a sharply increased adipogenic potential of AAA adventitial mesenchymal cells (P <.0001). Observed enrichment of adipocyte-related genes and pathways in ruptured AAA (P <.0003) supports an association between the extent of fatty degeneration and rupture. Conclusions: This translational study identifies extensive adventitial fatty degeneration as an ignored and distinctive feature of AAA disease. Enrichment of adipocyte genesis and adipocyte-related genes in ruptured AAA point to an association between the extent of fatty degeneration and rupture. This observation may (partly) explain the failure of medical therapy and could provide a lead for pharmaceutical alleviation of AAA progression. (J Vasc Surg 2018;67:1891-901.) Clinical Relevance: Although it is assumed AAA progression is driven by a proteolytic imbalance and inflammation, clinical studies consistently fail to show a benefit of medical interventions targeting these pathways. In this context, we sought further, currently unidentified mechanisms involved in (terminal) AAA wall weakening. This translational study identifies extensive adventitial fatty degeneration as a distinctive feature of advanced AAA disease. Enrichment of adipocyte-related genes in ruptured AAA wall samples implies an association between the extent of fatty degeneration and rupture.

• Dokumententyp: Zeitschriftenartikel
• Fakultät: Medizin
• Themengebiete: 600 Technik, Medizin, angewandte Wissenschaften > 610 Medizin und Gesundheit
• ISSN: 0741-5214
• Sprache: Englisch