Highly Selective PPARα (Peroxisome Proliferator-Activated Receptor α) Agonist Pemafibrate Inhibits Stent Inflammation and Restenosis Assessed by Multimodality Molecular-Microstructural Imaging

BACKGROUND

New pharmacological approaches are needed to prevent stent restenosis. This study tested the hypothesis that pemafibrate, a novel clinical selective PPARα (peroxisome proliferator‐activated receptor α) agonist, suppresses coronary stent‐induced arterial inflammation and neointimal hyperplasia.

METHODS AND RESULTS

Yorkshire pigs randomly received either oral pemafibrate (30 mg/day; n=6) or control vehicle (n=7) for 7 days, followed by coronary arterial implantation of 3.5 × 12 mm bare metal stents (2–4 per animal; 44 stents total). On day 7, intracoronary molecular‐structural near‐infrared fluorescence and optical coherence tomography imaging was performed to assess the arterial inflammatory response, demonstrating that pemafibrate reduced stent‐induced inflammatory protease activity (near‐infrared fluorescence target‐to‐background ratio: pemafibrate, median [25th‐75th percentile]: 2.8 [2.5–3.3] versus control, 4.1 [3.3–4.3], P=0.02). At day 28, animals underwent repeat near‐infrared fluorescence–optical coherence tomography imaging and were euthanized, and coronary stent tissue molecular and histological analyses. Day 28 optical coherence tomography imaging showed that pemafibrate significantly reduced stent neointima volume (pemafibrate, 43.1 [33.7–54.1] mm³ versus control, 54.2 [41.2–81.1] mm³; P=0.03). In addition, pemafibrate suppressed day 28 stent‐induced cellular inflammation and neointima expression of the inflammatory mediators TNF‐α (tumor necrosis factor‐α) and MMP‐9 (matrix metalloproteinase 9) and enhanced the smooth muscle differentiation markers calponin and smoothelin. In vitro assays indicated that the STAT3 (signal transducer and activator of transcription 3)–myocardin axes mediated the inhibitory effects of pemafibrate on smooth muscle cell proliferation.

CONCLUSIONS

Pemafibrate reduces preclinical coronary stent inflammation and neointimal hyperplasia following bare metal stent deployment. These results motivate further trials evaluating pemafibrate as a new strategy to prevent clinical stent restenosis.

Elevated Heart Rate in Combination with Elevated Blood Pressure Predicts Lower Cardiovascular Mortality in Acute Decompensated Heart Failure

Despite its clinical relevance, a subclass of acute decompensated heart failure (ADHF) with elevated blood pressure, known as hypertensive ADHF (HT-ADHF), has been less intensively evaluated. This study aimed to characterize the prognostic nature and pathophysiology of HT-ADHF. A total of 509 consecutive patients with first-time ADHF hospitalization were subjects of the study. Participants were divided into two groups: an HT-ADHF group (systolic blood pressure, SBP > 140 mmHg at presentation) and a non-HT-ADHF group (SBP ≤ 140 mmHg). Median follow-up duration measured 253 days. Unadjusted Kaplan-Meier analysis demonstrated both a lower cardiovascular mortality rate in the HT-ADHF group and similar incidences of heart failure rehospitalization in both groups. Adjusted Cox hazard analysis showed an association of elevated SBP at presentation with significantly lower cardiovascular mortality, though no such association was observed with heart failure rehospitalization. Moreover, elevated heart rate in combination with elevated SBP at presentation predicted a significantly lower risk of cardiovascular mortality (Hazard Ratio: 0.32, 95% CI: 0.14-0.77, P = 0.01). Also, significantly lower cardiovascular mortality was observed in this subtype, compared with other types of ADHF.

Successful Coronary Flow Restoration by Stent-Free Strategy Using the Pull-Back Method of Cutting Balloon in Spontaneous Coronary Artery Dissection

This report describes a 46-year-old woman with ST-elevation myocardial infarction due to spontaneous coronary artery dissection. Because continuous chest pain and ST-segment elevation in electrocardiography indicated ongoing cardiac ischemia, the urgent revascularization strategy was used using a novel method of cutting balloon angioplasty, “the pull-back of inflated cutting balloon,” which led to the successful coronary flow restoration and complete healing of dissected coronary artery in 1 year. The pull-back of the inflated cutting balloon method is a useful therapeutic option in the treatment of patients with spontaneous coronary artery dissection with ongoing cardiac ischemia.

PARP9 and PARP14 cross-regulate macrophage activation via STAT1 ADP-ribosylation

Despite the global impact of macrophage activation in vascular disease, the underlying mechanisms remain obscure. Here we show, with global proteomic analysis of macrophage cell lines treated with either IFNγ or IL-4, that PARP9 and PARP14 regulate macrophage activation. In primary macrophages, PARP9 and PARP14 have opposing roles in macrophage activation. PARP14 silencing induces pro-inflammatory genes and STAT1 phosphorylation in M(IFNγ) cells, whereas it suppresses anti-inflammatory gene expression and STAT6 phosphorylation in M(IL-4) cells. PARP9 silencing suppresses pro-inflammatory genes and STAT1 phosphorylation in M(IFNγ) cells. PARP14 induces ADP-ribosylation of STAT1, which is suppressed by PARP9. Mutations at these ADP-ribosylation sites lead to increased phosphorylation. Network analysis links PARP9-PARP14 with human coronary artery disease. PARP14 deficiency in haematopoietic cells accelerates the development and inflammatory burden of acute and chronic arterial lesions in mice. These findings suggest that PARP9 and PARP14 cross-regulate macrophage activation.