Epithelial Neutrophil-Activating Peptide (ENA-78), Acute Coronary Syndrome Prognosis, and Modulatory Effect of Statins

Endothelial inflammation with chemokine involvement contributes to acute coronary syndromes (ACS). We tested the hypothesis that variation in the chemokine gene CXCL5, which encodes epithelial neutrophil-activating peptide (ENA-78), is associated with ACS prognosis. We also investigated whether statin use, a potent modulator of inflammation, modifies CXCL5's association with outcomes and characterized the in vitro effect of atorvastatin on endothelial ENA-78 production. Using a prospective cohort of ACS patients (n = 704) the association of the CXCL5 −156 G>C polymorphism (rs352046) with 3-year all-cause mortality was estimated with hazard ratios (HR). Models were stratified by genotype and race. To characterize the influence of statins on this association, a statin*genotype interaction was tested. To validate ENA-78 as a statin target in inflammation typical of ACS, endothelial cells (HUVECs) were treated with IL-1β and atorvastatin with subsequent quantification of CXCL5 expression and ENA-78 protein concentrations. C/C genotype was associated with a 2.7-fold increase in 3-year all-cause mortality compared to G/G+G/C (95%CI 1.19–5.87; p = 0.017). Statins significantly reduced mortality in G/G individuals only (58% relative risk reduction; p = 0.0009). In HUVECs, atorvastatin dose-dependently decreased IL-1β-stimulated ENA-78 concentrations (p<0.0001). Drug effects persisted over 48 hours (p<0.01). CXCL5 genotype is associated with outcomes after ACS with potential statin modification of this effect. Atorvastatin lowered endothelial ENA-78 production during inflammation typical of ACS. These findings implicate CXCL5/ENA-78 in ACS and the statin response

Adjusted hazard ratio and 95% confidence intervals for all-cause mortality by genotype.

<p>Top panel is overall population (p = 0.017) and bottom panel is Caucasians only (p = 0.043). Models adjusted for age, race, sex, ACS type, revascularization strategy, history of diabetes, and history of heart failure.</p

Kaplan Meier estimates for all-cause mortality by <i>CXCL5</i> −156 G>C genotype.

<p>Panel A represents the overall population; panel B represents the Caucasians only.</p

Atorvastatin effects on ENA-78 are reversed by mevalonate and its downstream metabolites.

<p>Data are presented as mean±SEM of 10 experiments. *p<0.001 and †p = 0.05 compared to IL-1β stimulation alone. AT, atorvastatin; FPP, farnesyl pyrophosphate; GGPP, geranylgeranyl pyrophosphate; MEV, mevalonate.</p

Atorvastatin attenuates ENA-78 production over time.

<p>Levels are relative to baseline (0 hour) for each condition. Data are presented as mean±SEM of 4 experiments. *p≤0.01. —○—, IL-1β stimulation+atorvastatin 10 µM; —•—, IL-1β stimulation alone; AT, atorvastatin.</p

Baseline Characteristics.

<p>*n = 603; ^†n = 594; ^‡n = 565; ^§n = 593; ACS = Acute coronary syndrome; MI = Myocardial infarction; LBB = Left bundle block; HTN = Hypertension; BMI = Body mass index; EF = Ejection fraction; SBP = Systolic blood pressure; DBP = Diastolic blood pressure; HDL = High density lipoprotein; LDL = Low density lipoprotein; PCI = Percutaneous coronary intervention; CABG = Coronary artery bypass graft.</p

<i>CXCL5</i> expression is modulated by atorvastatin and IL-1β.

<p>(A) Gel electrophoresis of <i>CXCL5</i> and <i>GAPDH</i> PCR products; (B) Log₁₀ relative quantification of <i>CXCL5</i> modulated by atorvastatin, IL-1β, and their combination normalized to <i>GAPDH</i> (N = 2 experiments). *P<0.005, †P<0.0001. AT, atorvastatin.</p

Atorvastatin attenuates IL-1β-induced ENA-78 production in a dose-dependent fashion.

<p>Data are presented as mean±SEM of 4 experiments. * p<0.0001 vs. IL-1β, †p = NS vs. control. AT, atorvastatin.</p