The Netherlands Organisation for Health Research and Development, and the NutsOhra Fund.

Statins are thought to reduce vascular inflammation through lipid independent mechanisms. Evaluation of such an effect in atherosclerotic disease is complicated by simultaneous effects on lipid metabolism. Abdominal aortic aneurysms (AAA) are part of the atherosclerotic spectrum of diseases. Unlike atherosclerotic occlusive disease, AAA is not lipid driven, thus allowing direct evaluation of putative anti-inflammatory effects. The anti-inflammatory potency of increasing doses (0, 20 or 40 mg/day) simvastatin or atorvastatin was evaluated in 63 patients that were at least 6 weeks on statin therapy and who underwent open AAA repair. A comprehensive analysis using immunohistochemistry, mRNA and protein analyses was applied on aortic wall samples collected during surgery. The effect of statins on AAA growth was analyzed in a separate prospective study in incorporating 142 patients. Both statins equally effectively and dose-dependently reduced aortic wall expression of NFκB regulated mediators (i.e. IL-6 (P<0.001) and MCP-1 (P<0.001)); shifted macrophage polarization towards a M2 phenotype (P<0.0003); selectively reduced macrophage-related markers such as cathepsin K and S (P<0.009 and 0.0027 respectively), and ALOX5 (P<0.0009), and reduced vascular wall NFκB activity (40 mg/day group, P<0.016). No effect was found on other cell types. Evaluation of the clinical efficacy of statins to reduce AAA progression did not indicate an effect of statins on aneurysm growth (P<0.337). Hence, in the context of AAA the clinical relevance of statins pleiotropy appears minimal.

BackgroundIndependent of their blood pressure lowering effect, ACE inhibitors are thought to reduce vascular inflammation. The clinical relevance of this effect is unclear with the current knowledge. Abdominal aortic aneurysms (AAA) are characterized by a broad, non-specific inflammatory response, and thus provide a clinical platform to evaluate the anti-inflammatory potential of ACE inhibitors.Methods and ResultsEleven patients scheduled for open AAA repair received ramipril (5 mg/day) during 2–4 weeks preceding surgery. Aortic wall samples were collected during surgery, and compared to matched samples obtained from a biobank. An anti-inflammatory potential was evaluated in a comprehensive analysis that included immunohistochemistry, mRNA and protein analysis. A putative effect of ACE inhibitors on AAA growth was tested separately by comparing 18-month growth rate of patients on ACE inhibitors (n = 82) and those not taking ACE inhibitors (n = 204). Ramipril reduces mRNA expression of multiple pro-inflammatory cytokines such as IL-1β, IL-6, IL-8, TNF -α, Interferon-, and MCP-1, as well as aortic wall IL-8 and MCP-1 (P = 0.017 and 0.008, respectively) protein content. The is followed by clear effects on cell activation that included a shift towards anti-inflammatory macrophage (M2) subtype. Evaluation of data from the PHAST cohort did not indicate an effect of ACE inhibitors on 18-month aneurysm progression (mean difference at 18 months: −0.24 mm (95% CI: −0.90–0.45, P = NS).ConclusionsACE inhibition quenches multiple aspects of vascular inflammation in AAA. However, this does not translate into reduced aneurysm growth.Trial RegistrationNederlands Trial Register 1345.

This study confirms an association between AAA and COPD and shows that this association is independent from smoking. Findings also demonstrate that COPD is under-diagnosed in AAA patients.

Animal studies implicate the AP-1 (activator protein-1) pro-inflammatory pathway as a promising target in the treatment of atherosclerotic disease. It is, however, unclear whether these observations apply to human atherosclerosis. Therefore we evaluated the profile of AP-1 activation through histological analysis and tested the potential benefit of AP-1 inhibition in a clinical trial. AP-1 activation was quantified by phospho-c-Jun nuclear translocation (immunohistochemistry) on a biobank of aortic wall samples from organ donors. The effect of AP-1 inhibition on vascular parameters was tested through a double blind placebo-controlled cross-over study of 28 days doxycycline or placebo in patients with symptomatic peripheral artery disease. Vascular function was assessed by brachial dilation as well as by plasma samples analysed for hs-CRP (high-sensitivity C-reactive protein), IL-6 (interleukin-6), IL-8, ICAM-1 (intercellular adhesion molecule-1), vWF (von Willebrand factor), MCP-1 (monocyte chemoattractant protein-1), PAI-1 (plasminogen activator inhibitor-1) and fibrinogen. Histological evaluation of human atherosclerosis showed minimal AP-1 activation in non-diseased arterial wall (i.e. vessel wall without any signs of atherosclerotic disease). A gradual increase of AP-1 activation was found in non-progressive and progressive phases of atherosclerosis respectively (P<0.044). No significant difference was found between progressive and vulnerable lesions. The expression of phospho-c-Jun diminished as the lesion stabilized (P<0.016) and does not significantly differ from the normal aortic wall (P<0.33). Evaluation of the doxycycline intervention only revealed a borderline-significant reduction of circulating hs-CRP levels (−0.51 μg/ml, P=0.05) and did not affect any of the other markers of systemic inflammation and vascular function. Our studies do not characterize AP-1 as a therapeutic target for progressive human atherosclerotic disease.