Myocardial ischemia-reperfusion (IR) injury limits the therapeutic effect of early reperfusion therapy for acute myocardial infarction (AMI), in which the recruitment of inflammatory monocytes plays a causative role. Here we develop bioabsorbable poly-lactic/glycolic acid (PLGA) nanoparticles incorporating irbesartan, an angiotensin II type 1 receptor blocker with a peroxisome proliferator-activated receptor (PPAR)γ agonistic effect (irbesartan-NP). In a mouse model of IR injury, intravenous PLGA nanoparticles distribute to the IR myocardium and monocytes in the blood and in the IR heart. Single intravenous treatment at the time of reperfusion with irbesartan-NP (3.0 mg kg⁻¹ irbesartan), but not with control nanoparticles or irbesartan solution (3.0 mg kg⁻¹), inhibits the recruitment of inflammatory monocytes to the IR heart and reduces the infarct size via PPARγ-dependent anti-inflammatory mechanisms and ameliorates left ventricular remodeling 21 days after IR. Irbesartan-NP is a novel approach to treat myocardial IR injury in patients with AMI.

Objective—: Inflammatory monocytes/macrophages produce various proteinases, including matrix metalloproteinases, and degradation of the extracellular matrix by these activated proteinases weakens the mechanical strength of atherosclerotic plaques, which results in a rupture of the plaque. Peroxisome proliferator–activated receptor-γ induces a polarity shift of monocytes/macrophages toward less inflammatory phenotypes and has the potential to prevent atherosclerotic plaque ruptures. Therefore, we hypothesized that nanoparticle-mediated targeted delivery of the peroxisome proliferator–activated receptor-γ agonist pioglitazone into circulating monocytes could effectively inhibit plaque ruptures in a mouse model. Approach and Results—: We prepared bioabsorbable poly(lactic- co -glycolic-acid) nanoparticles containing pioglitazone (pioglitazone-NPs). Intravenously administered poly(lactic- co -glycolic-acid) nanoparticles incorporated with fluorescein isothiocyanate were found in circulating monocytes and aortic macrophages by flow cytometric analysis. Weekly intravenous administration of pioglitazone-NPs (7 mg/kg per week) for 4 weeks decreased buried fibrous caps, a surrogate marker of plaque rupture, in the brachiocephalic arteries of ApoE ^−/− mice fed a high-fat diet and infused with angiotensin II. In contrast, administration of control-NPs or an equivalent dose of oral pioglitazone treatment produced no effects. Pioglitazone-NPs inhibited the activity of matrix metalloproteinases and cathepsins in the brachiocephalic arteries. Pioglitazone-NPs regulated inflammatory cytokine expression and also suppressed the expression of extracellular matrix metalloproteinase inducer in bone marrow–derived macrophages. Conclusions—: Nanoparticle-mediated delivery of pioglitazone inhibited macrophage activation and atherosclerotic plaque ruptures in hyperlipidemic ApoE ^−/− mice. These results demonstrate a promising strategy with a favorable safety profile to prevent atherosclerotic plaque ruptures.

Background: Mitochondria‐mediated cell death plays a critical role in myocardial ischemia‐reperfusion ( IR ) injury. We hypothesized that nanoparticle‐mediated drug delivery of mitochondrial division inhibitor 1 (Mdivi1) protects hearts from IR injury through inhibition of mitochondria outer membrane permeabilization ( MOMP ), which causes mitochondrial‐mediated cell death. Methods and Results: We formulated poly (lactic‐co‐glycolic acid) nanoparticles containing Mdivi1 (Mdivi1‐ NP ). We recently demonstrated that these nanoparticles could be successfully delivered to the cytosol and mitochondria of cardiomyocytes under H ₂ O ₂ ‐induced oxidative stress that mimicked IR injury. Pretreatment with Mdivi1‐ NP ameliorated H ₂ O ₂ ‐induced cell death in rat neonatal cardiomyocytes more potently than Mdivi1 alone, as indicated by a lower estimated half‐maximal effective concentration and greater maximal effect on cell survival. Mdivi1‐ NP treatment of Langendorff‐perfused mouse hearts through the coronary arteries at the time of reperfusion reduced infarct size after IR injury more effectively than Mdivi1 alone. Mdivi1‐ NP treatment also inhibited Drp1‐mediated Bax translocation to the mitochondria and subsequent cytochrome c leakage into the cytosol, namely, MOMP , in mouse IR hearts. MOMP inhibition was also observed in cyclophilin D knockout (CypD‐ KO ) mice, which lack the mitochondrial permeability transition pore ( MPTP ) opening. Intravenous Mdivi1‐ NP treatment in vivo at the time of reperfusion reduced IR injury in wild‐type and CypD‐ KO mice, but not Bax‐ KO mice. Conclusions: Mdivi1‐ NP treatment reduced IR injury through inhibition of MOMP , even in the absence of a CypD/ MPTP opening. Thus, nanoparticle‐mediated drug delivery of Mdivi1 may be a novel treatment strategy for IR injury.

Coronary artery disease, in the development of which inflammation mediated by innate immune cells plays a critical role, is one of the leading causes of death worldwide. The 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) are a widely used lipid-lowering drug that has lipid-independent vasculoprotective effects, such as improvement of endothelial dysfunction, antioxidant properties, and inhibitory effects on inflammation. Despite recent advances in lipid-lowering therapy, clinical trials of statins suggest that anti-inflammatory therapy beyond lipid-lowering therapy is indispensible to further reduce cardiovascular events. One possible therapeutic option to the residual risk is to directly intervene in the inflammatory process by utilizing a nanotechnology-based drug delivery system (nano-DDS). Various nano-sized materials are currently developed as DDS, including micelles, liposomes, polymeric nanoparticles, dendrimers, carbon nanotubes, and metallic nanoparticles. The application of nano-DDS to coronary artery disease is a feasible strategy since the inflammatory milieu enhances incorporation of nano-sized materials into mononuclear phagocytic system and permeability of target lesions, which confers nano-DDS on “passive-targeting” property. Recently, we have developed a polymeric nanoparticle-incorporating statin to maximize its anti-inflammatory property. This statin nanoparticle has been tested in various disease models, including plaque destabilization and rupture, myocardial ischemia-reperfusion injury, and ventricular remodeling after acute myocardial infarction, and its clinical application is in progress. In this review, we present current development of DDS and future perspective on the application of anti-inflammatory nanomedicine to treat life-threatening cardiovascular diseases.

Background: Early bleeding after percutaneous coronary intervention is associated with increased risk of death and myocardial infarction; however, the association between bleeding and subsequent major adverse cardiac and cerebrovascular events (MACCE) remains unclear in patients with atrial fibrillation and stable coronary artery disease. We thus aimed to investigate this association. Methods: The AFIRE trial (Atrial Fibrillation and Ischemic Events With Rivaroxaban in Patients With Stable Coronary Artery Disease) was a multicenter, open-label trial conducted in Japan. This post hoc analysis included 2215 patients with atrial fibrillation and stable coronary artery disease treated with rivaroxaban or rivaroxaban plus an antiplatelet agent. MACCE was defined as a composite of stroke, systemic embolism, myocardial infarction, unstable angina requiring revascularization, or death from any cause. The association of bleeding with subsequent MACCE risk was investigated using time-adjusted Cox multivariate analysis after adjusting for baseline characteristics and time from bleeding. Bleeding events were classified according to the International Society on Thrombosis and Haemostasis criteria. Results: Among the 2215 patients, 386 (17.4%) had bleeding during follow-up, of whom 63 (16.3%) also experienced MACCE; MACCE incidence was higher in patients with bleeding than in those without (8.38% versus 4.20% per patient-year; hazard ratio, 2.01 [95% CI, 1.49–2.70]; P <0.001). The proportion of patients with both bleeding and MACCE (developed after bleeding) was 73.0% (46 of 63); 27.0% (17 of 63) experienced MACCE before bleeding. Time-adjusted Cox multivariate analysis revealed a temporal association between major bleeding and subsequent MACCE, with particularly high MACCE risks within 30 days after major bleeding (hazard ratio, 7.81 [95% CI, 4.20–14.54]). Conclusions: In patients with atrial fibrillation and stable coronary artery disease, major bleeding was strongly associated with subsequent MACCE. Thus, it is important to prevent major bleeding to avoid cardiovascular events and death. Registration: URL: https://www.umin.ac.jp/ctr ; Unique identifier: UMIN000016612. URL: https://www.clinicaltrials.gov ; Unique identifier: NCT02642419. Graphic A graphic abstract is available for this article.