Relationship between the number of drugs used during percutaneous coronary intervention and adverse events in patients with chronic coronary syndrome: Analysis of CLIDAS database.

Background: Polypharmacy is associated with an increased risk of adverse events due to the higher number of drugs used. This is particularly notable in patients with chronic coronary syndrome (CCS), who are known to use a large number of drugs. Therefore, we investigated polypharmacy in patients with CCS, using CLIDAS, a multicenter database of patients who underwent percutaneous coronary intervention. Method and results: Between 2017 and 2020, 1411 CCS patients (71.5 ± 10.5 years old; 77.3 % male) were enrolled. The relationship between cardiovascular events occurring during the median follow-up of 514 days and the number of drugs at the time of PCI was investigated. The median number of drugs prescribed was nine. Major adverse cardiovascular events (MACE), defined as cardiovascular death, myocardial infarction, stroke, heart failure, transient ischemic attack, or unstable angina, occurred in 123 patients, and all-cause mortality occurred in 68 patients. For each additional drug, the adjusted hazard ratios for MACE and all-cause mortality increased by 2.069 (p = 0.003) and 1.102 (p = 0.010). The adjusted hazard ratios for MACE and all-cause mortality were significantly higher in the group using nine or more drugs compared to the group using eight or fewer drugs (1.646 and 2.253, both p < 0.001). Conclusion: This study showed that an increase in the number of drugs used for CCS may be associated with MACE and all-cause mortality. In patients with CCS, it might be beneficial to minimize the number of medications as much as possible, while managing comorbidities and using guideline-recommended drugs.

Cyclophilin D induces necrotic core formation by mediating mitochondria-associated macrophage death in advanced atherosclerotic lesions.

BACKGROUND AND AIMS: In advanced atherosclerotic lesions, macrophage deaths result in necrotic core formation and plaque vulnerability. Cyclophilin D (CypD) is a mitochondria-specific cyclophilin involved in the process of cell death after organ ischemia-reperfusion. However, the role of CypD in atherosclerosis, especially in necrotic core formation, is unknown. Therefore, this experiment aims to clarify the role of CypD in necrotic core formation. METHODS: To clarify the specific role of CypD, encoded by Ppif in mice, apolipoprotein-E/CypD-double knockout (Apoe-/-Ppif-/-) mice were generated. These mice were fed a high-fat diet containing 0.15 % cholesterol for 24 weeks to accelerate atherosclerotic lesion development. RESULTS: Deletion of CypD decreased the necrotic core size, accompanied by a reduction of macrophage apoptosis compared to control Apoe-/- mice. In RAW264.7 cells, siRNA-mediated knockdown of CypD attenuated the release of cytochrome c from the mitochondria to the cytosol induced by endoplasmic reticulum stress inducer thapsigargin. In addition, necroptosis, induced by TNF-α and caspase inhibitor, was attenuated by knockdown of CypD. Ly-6Chigh inflammatory monocytes in peripheral blood leukocytes and mRNA expression of Il1b in the aorta were decreased by deletion of CypD. In contrast, siRNA-mediated knockdown of CypD did not significantly decrease Il1b nor Ccl2 mRNA expression in RAW264.7 cells treated with LPS and IFN-γ, suggesting that inhibition of inflammation in vivo is likely due to decreased cell death in the atherosclerotic lesions rather than a direct action of CypD deletion on the macrophage. CONCLUSIONS: These results indicate that CypD induces macrophage death and mediates necrotic core formation in advanced atherosclerotic lesions. CypD could be a novel therapeutic target for treating atherosclerotic vascular diseases.

EVs-miR-17-5p attenuates the osteogenic differentiation of vascular smooth muscle cells potentially via inhibition of TGF-ß signaling under high glucose conditions.

Vascular calcification, which is a major complication of diabetes mellitus, is an independent risk factor for cardiovascular disease. Osteogenic differentiation of vascular smooth muscle cells (VSMCs) is one of the key mechanisms underlying vascular calcification. Emerging evidence suggests that macrophage-derived extracellular vesicles (EVs) may be involved in calcification within atherosclerotic plaques in patients with diabetes mellitus. However, the role of macrophage-derived EVs in the progression of vascular calcification is largely unknown. In this study, we investigated whether macrophage-derived EVs contribute to the osteogenic differentiation of VSMCs under high glucose conditions. We isolated EVs that were secreted by murine peritoneal macrophages under normal glucose (EVs-NG) or high glucose (EVs-HG) conditions. miRNA array analysis in EVs from murine macrophages showed that miR-17-5p was significantly increased in EVs-HG compared with EVs-NG. Prediction analysis with miRbase identified transforming growth factor ß receptor type II (TGF-ß RII) as a potential target of miR-17-5p. EVs-HG as well as miR-17-5p overexpression with lipid nanoparticles inhibited the gene expression of Runx2, and TGF-ß RII. Furthermore, we demonstrated that VSMCs transfected with miR-17-5p mimic inhibited calcium deposition. Our findings reveal a novel role of macrophage-derived EVs in the negative regulation of osteogenic differentiation in VSMCs under high glucose conditions.

Association between Familial Hypercholesterolemia and Serum Levels of Cholesterol Synthesis and Absorption Markers: The CACHE Study FH Analysis.

AIM: Serum levels of cholesterol absorption and synthesis markers are known to be associated with cardiovascular risk. Familial hypercholesterolemia (FH) is a well-known inherited disorder presenting elevated low-density lipoprotein cholesterol (LDL-C) and total cholesterol (TC) levels and premature coronary disease. In this study, we aim to examine the differences in terms of serum markers of cholesterol metabolism between FH and non-FH individuals and to examine their associations with serum lipid levels. METHODS: In this study, we utilized data on serum markers of cholesterol metabolism, namely, lathosterol (Latho, synthesis marker), campesterol (Campe, absorption marker), and sitosterol (Sito, absorption marker) measured by gas chromatography of the CACHE consortium, which comprised of 13 research groups in Japan. Clinical data were compiled using REDCap system. Among the 2944 individuals in the CACHE population, we selected individuals without lipid-lowering medications and hemodialysis patients for this CACHE study FH analysis. Multivariable adjustment was performed to assess the associations. RESULTS: In this study, we analyzed data from 51 FH patients and 1924 non-FH individuals. After adjustment for possible confounders, the FH group was shown to have significantly higher Campe and Sito concentrations and insignificantly higher Latho concentrations than the non-FH group. These marker concentrations showed nonlinear associations with TC in the FH group. Campe/Latho and Sito/Latho ratios were significantly higher in the FH group than in the non-FH group. CONCLUSION: FH group had significantly elevated serum Campe and Sito concentrations and insignificantly elevated Latho concentrations; thus, intestinal cholesterol absorption relative to hepatic cholesterol synthesis was suggested to be elevated in patients with FH. Serum Latho, Campe, and Sito concentrations showed nonlinear associations with TC in the FH group.

Identifying Hyperreflective Foci in Diabetic Retinopathy via VEGF-Induced Local Self-Renewal of CX3CR1+ Vitreous Resident Macrophages.

Intraretinal hyperreflective foci (HRF) are significant biomarkers for diabetic macular edema. However, HRF at the vitreoretinal interface (VRI) have not been examined in diabetic retinopathy (DR). A prospective observational clinical study with 162 consecutive eyes using OCT imaging showed significantly increased HRF at the VRI during DR progression (P < 0.01), which was reversed by anti-vascular endothelial growth factor (VEGF) therapy. F4/80+ macrophages increased significantly at the VRI in Kimba (vegfa+/+) or Akimba (Akita × Kimba) mice (both P < 0.01), but not in diabetic Akita (Ins2+/-) mice, indicating macrophage activation was modulated by elevated VEGF rather than the diabetic milieu. Macrophage depletion significantly reduced HRF at the VRI (P < 0.01). Furthermore, BrdU administration in Ccr2rfp/+Cx3cr1gfp/+vegfa+/- mice identified a significant contribution of M2-like tissue-resident macrophages (TRMs) at the VRI. Ki-67+ and CD11b+ cells were observed in preretinal tissues of DR patients, while exposure of vitreal macrophages to vitreous derived from PDR patients induced a significant proliferation response in vitro (P < 0.01). Taken together, the evidence suggests that VEGF drives a local proliferation of vitreous resident macrophages (VRMs) at the VRI during DR. This phenomenon helps to explain the derivation and disease-relevance of the HRF lesions observed through OCT imaging in patients.

Dietary 7-ketocholesterol exacerbates myocardial ischemia-reperfusion injury in mice through monocyte/macrophage-mediated inflammation.

Emerging evidence suggests that 7-ketocholesterol (7-KC), one of the most abundant dietary oxysterols, causes inflammation and cardiovascular diseases. Here we show the deteriorating effects of dietary 7-KC on myocardial ischemia-reperfusion (IR) injury and detailed the molecular mechanisms. A high-fat high-cholesterol diet containing 7-KC (7KWD) for 3 weeks increased the plasma 7-KC level compared with high-fat high-cholesterol diet in mice. In wild-type mice but not in CCR2-/- mice, dietary 7-KC increased the myocardial infarct size after IR. Flow cytometry revealed that the ratio of Ly-6Chigh inflammatory monocytes to total monocytes was increased in the 7KWD group. Unbiased RNA sequencing using murine primary macrophages revealed that 7-KC regulated the expression of transcripts related to inflammation and cholesterol biosynthesis. We further validated that in vitro, 7-KC induced endoplasmic reticulum stress, mitochondrial reactive oxygen species production, and nuclear factor-kappa B activation, which are associated with increased mRNA levels of proinflammatory cytokines. Administration of N-acetyl-L-cysteine or siRNA-mediated knockdown of PKR-like endoplasmic reticulum kinase or endoplasmic reticulum oxidase 1α suppressed the levels of 7-KC-induced inflammation. Dietary 7-KC exacerbates myocardial IR injury through monocyte/macrophage-mediated inflammation. Endoplasmic reticulum stress and oxidative stress are involved in the 7-KC-induced proinflammatory response in macrophages.

Nanoparticle-Mediated Delivery of Pitavastatin to Monocytes/Macrophages Inhibits Angiotensin II-Induced Abdominal Aortic Aneurysm Formation in Apoe-/- Mice.

AIM: Abdominal aortic aneurysm (AAA) is a lethal and multifactorial disease. To prevent a rupture and dissection of enlarged AAA, prophylactic surgery and stenting are currently available. There are, however, no medical therapies preventing these complications of AAA. Statin is one of the candidates, but its efficacy on AAA formation/progression remains controversial. We have previously demonstrated that nanoparticles (NPs) incorporating pitavastatin (Pitava-NPs)-clinical trials using these nanoparticles have been already conducted-suppressed progression of atherosclerosis in apolipoprotein E-deficient ( Apoe-/-) mice. Therefore, we have tested a hypothesis that monocytes/macrophages-targeting delivery of pitavastatin prevents the progression of AAA. METHODS: Angiotensin II was intraperitoneally injected by osmotic mini-pumps to induce AAA formation in Apoe-/- mice. NPs consisting of poly(lactic-co-glycolic acid) were used for in vivo delivery of pitavastatin to monocytes/macrophages. RESULTS: Intravenously administered Pitava-NPs (containing 0.012 mg/kg/week pitavastatin) inhibited AAA formation accompanied with reduction of macrophage accumulation and monocyte chemoattractant protein-1 (MCP-1) expression. Ex vivo molecular imaging revealed that Pitava-NPs not only reduced macrophage accumulation but also attenuated matrix metalloproteinase activity in the abdominal aorta, which was underpinned by attenuated elastin degradation. CONCLUSION: These results suggest that Pitava-NPs inhibit AAA formation associated with reduced macrophage accumulation and MCP-1 expression. This clinically feasible nanomedicine could be an innovative therapeutic strategy that prevents devastating complications of AAA.

Aspirin versus P2Y12 inhibitors with anticoagulation therapy for atrial fibrillation.

OBJECTIVE: Patients with coronary artery disease (CAD) and atrial fibrillation (AF) can be treated with multiple antithrombotic therapies including antiplatelet and anticoagulant therapies; however, this has the potential to increase bleeding risk. Here, we aimed to evaluate the efficacy and safety of P2Y12 inhibitors and aspirin in patients also receiving anticoagulant therapy. METHODS: We evaluated patients from the Atrial Fibrillation and Ischaemic Events with Rivaroxaban in Patients with Stable Coronary Artery Disease (AFIRE) trial who received rivaroxaban plus an antiplatelet agent; the choice of antiplatelet agent was left to the physician's discretion. The primary efficacy and safety end points, consistent with those of the AFIRE trial, were compared between P2Y12 inhibitors and aspirin groups. The primary efficacy end point was a composite of stroke, systemic embolism, myocardial infarction, unstable angina requiring revascularisation or death from any cause. The primary safety end point was major bleeding according to the International Society on Thrombosis and Haemostasis criteria. RESULTS: A total of 1075 patients were included (P2Y12 inhibitor group, n=297; aspirin group, n=778). Approximately 60% of patients were administered proton pump inhibitors (PPIs) and there was no significant difference in PPI use in the groups. There were no significant differences in the primary end points between the groups (efficacy: HR 1.31; 95% CI 0.88 to 1.94; p=0.178; safety: HR 0.79; 95% CI 0.43 to 1.47; p=0.456). CONCLUSIONS: There were no significant differences in cardiovascular and bleeding events in patients with AF and stable CAD taking rivaroxaban with P2Y12 inhibitors or aspirin in the chronic phase. TRIAL REGISTRATION NUMBER: UMIN000016612; NCT02642419.

Institutional Characteristics and Prognosis of Acute Myocardial Infarction With Cardiogenic Shock in Japan　- Analysis From the JROAD/JROAD-DPC Database.

BACKGROUND: The high mortality of acute myocardial infarction (AMI) with cardiogenic shock (i.e., Killip class IV AMI) remains a challenge in emergency cardiovascular care. This study aimed to examine institutional factors, including the number of JCS board-certified members, that are independently associated with the prognosis of Killip class IV AMI patients.Methods and Results:In the Japanese registry of all cardiac and vascular diseases-diagnosis procedure combination (JROAD-DPC) database (years 2012-2016), the 30-day mortality of Killip class IV AMI patients (n=21,823) was 42.3%. Multivariate analysis identified age, female sex, admission by ambulance, deep coma, and cardiac arrest as patient factors that were independently associated with higher 30-day mortality, and the numbers of JCS board-certified members and of intra-aortic balloon pumping (IABP) cases per year as institutional factors that were independently associated with lower mortality in Killip class IV patients, although IABP was associated with higher mortality in Killip classes I-III patients. Among hospitals with the highest quartile (≥9 JCS board-certified members), the 30-day mortality of Killip class IV patients was 37.4%. CONCLUSIONS: A higher numbers of JCS board-certified members was associated with better survival of Killip class IV AMI patients. This finding may provide a clue to optimizing local emergency medical services for better management of AMI patients in Japan.

Antithrombotic Therapy for Atrial Fibrillation with Stable Coronary Disease.

BACKGROUND: There are limited data from randomized trials evaluating the use of antithrombotic therapy in patients with atrial fibrillation and stable coronary artery disease. METHODS: In a multicenter, open-label trial conducted in Japan, we randomly assigned 2236 patients with atrial fibrillation who had undergone percutaneous coronary intervention (PCI) or coronary-artery bypass grafting (CABG) more than 1 year earlier or who had angiographically confirmed coronary artery disease not requiring revascularization to receive monotherapy with rivaroxaban (a non-vitamin K antagonist oral anticoagulant) or combination therapy with rivaroxaban plus a single antiplatelet agent. The primary efficacy end point was a composite of stroke, systemic embolism, myocardial infarction, unstable angina requiring revascularization, or death from any cause; this end point was analyzed for noninferiority with a noninferiority margin of 1.46. The primary safety end point was major bleeding, according to the criteria of the International Society on Thrombosis and Hemostasis; this end point was analyzed for superiority. RESULTS: The trial was stopped early because of increased mortality in the combination-therapy group. Rivaroxaban monotherapy was noninferior to combination therapy for the primary efficacy end point, with event rates of 4.14% and 5.75% per patient-year, respectively (hazard ratio, 0.72; 95% confidence interval [CI], 0.55 to 0.95; P<0.001 for noninferiority). Rivaroxaban monotherapy was superior to combination therapy for the primary safety end point, with event rates of 1.62% and 2.76% per patient-year, respectively (hazard ratio, 0.59; 95% CI, 0.39 to 0.89; P = 0.01 for superiority). CONCLUSIONS: As antithrombotic therapy, rivaroxaban monotherapy was noninferior to combination therapy for efficacy and superior for safety in patients with atrial fibrillation and stable coronary artery disease. (Funded by the Japan Cardiovascular Research Foundation; AFIRE UMIN Clinical Trials Registry number, UMIN000016612; and ClinicalTrials.gov number, NCT02642419.).

Nanoparticle incorporating Toll-like receptor 4 inhibitor attenuates myocardial ischaemia-reperfusion injury by inhibiting monocyte-mediated inflammation in mice.

AIMS: Myocardial ischaemia-reperfusion (IR) injury hampers the therapeutic effect of revascularization in patients with acute myocardial infarction (AMI). Innate immunity for damage-associated protein patterns promotes the process of IR injury; however, the blockade of Toll-like receptor 4 (TLR4) in myocardial IR injury has not been translated into clinical practice. Therefore, we aimed to examine whether the nanoparticle-mediated administration of TAK-242, a chemical inhibitor of TLR4, attenuates myocardial IR injury in a clinically feasible protocol in a mouse model. METHODS AND RESULTS: We have prepared poly-(lactic-co-glycolic acid) nanoparticles containing TAK-242 (TAK-242-NP). TAK-242-NP significantly enhanced the drug delivery to monocytes/macrophages in the spleen, blood, and the heart in mice. Intravenous administration of TAK-242-NP (containing 1.0 or 3.0 mg/kg TAK-242) at the time of reperfusion decreased the infarct size, but the TAK-242 solution did not even when administered at a dosage of 10.0 mg/kg. TAK-242-NP inhibited the recruitment of Ly-6Chigh monocytes to the heart, which was accompanied by decreased circulating HMGB1, and NF-κB activation and cytokine expressions in the heart. TAK-242-NP did not decrease the infarct size further in TLR4-deficient mice, confirming the TLR4-specific mechanism in the effects of TAK-242-NP. Furthermore, TAK-242-NP did not decrease the infarct size further in CCR2-deficient mice, suggesting that monocyte/macrophage-mediated inflammation is the primary therapeutic target of TAK-242-NP. CONCLUSION: The nanoparticle-mediated delivery of TAK-242-NP represent a novel and clinical feasible strategy in patients undergone coronary revascularization for AMI by regulating TLR4-dependent monocytes/macrophages-mediated inflammation.

Peroxisome proliferator-activated receptor-gamma targeting nanomedicine promotes cardiac healing after acute myocardial infarction by skewing monocyte/macrophage polarization in preclinical animal models.

Aims: Monocyte-mediated inflammation is a major mechanism underlying myocardial ischaemia-reperfusion (IR) injury and the healing process after acute myocardial infarction (AMI). However, no definitive anti-inflammatory therapies have been developed for clinical use. Pioglitazone, a peroxisome proliferator-activated receptor-gamma (PPARγ) agonist, has unique anti-inflammatory effects on monocytes/macrophages. Here, we tested the hypothesis that nanoparticle (NP)-mediated targeting of pioglitazone to monocytes/macrophages ameliorates IR injury and cardiac remodelling in preclinical animal models. Methods and results: We formulated poly (lactic acid/glycolic acid) NPs containing pioglitazone (pioglitazone-NPs). In a mouse IR model, these NPs were delivered predominantly to circulating monocytes and macrophages in the IR heart. Intravenous treatment with pioglitazone-NPs at the time of reperfusion attenuated IR injury. This effect was abrogated by pre-treatment with the PPARγ antagonist GW9662. In contrast, treatment with a pioglitazone solution had no therapeutic effects on IR injury. Pioglitazone-NPs inhibited Ly6Chigh inflammatory monocyte recruitment as well as inflammatory gene expression in the IR hearts. In a mouse myocardial infarction model, intravenous treatment with pioglitazone-NPs for three consecutive days, starting 6 h after left anterior descending artery ligation, attenuated cardiac remodelling by reducing macrophage recruitment and polarizing macrophages towards the pro-healing M2 phenotype. Furthermore, pioglitazone-NPs significantly decreased mortality after MI. Finally, in a conscious porcine model of myocardial IR, pioglitazone-NPs induced cardioprotection from reperfused infarction, thus providing pre-clinical proof of concept. Conclusion: NP-mediated targeting of pioglitazone to inflammatory monocytes protected the heart from IR injury and cardiac remodelling by antagonizing monocyte/macrophage-mediated acute inflammation and promoting cardiac healing after AMI.

Nanoparticle-Mediated Delivery of Pitavastatin to Monocytes/Macrophages Inhibits Left Ventricular Remodeling After Acute Myocardial Infarction by Inhibiting Monocyte-Mediated Inflammation.

Left ventricular (LV) remodeling after myocardial infarction (MI) causes heart failure. Although medical therapies including angiotensin converting enzyme inhibitors show inhibitory effects on post-infarct LV remodeling, the prognosis of patients with post-infarct heart failure is still poor. Accumulating evidence suggests that an inflammatory response is implicated in the process of post-infarct LV remodeling. Therefore, we hypothesized that anti-inflammatory therapy by nanoparticle-mediated monocyte/macrophage-targeting delivery of pitavastatin may protect the heart from post-infarct LV remodeling.Male C57BL/6 mice were subjected to permanent coronary ligation and pitavastatin-incorporating nanoparticles (Pitavastatin-NPs) were intravenously injected for 3 to 5 consecutive days. Pitavastatin-NPs were delivered to CD11b+ monocytes/macrophages, but not to cardiomyocytes. Treatment with Pitavastatin-NPs after establishment of MI attenuated post-infarct LV remodeling accompanied by a reduction of monocytes/macrophages in the heart, whereas pitavastatin solution treatment did not. Pitavastatin-NPs inhibited mobilization of monocytes from the spleen after MI. In mice after splenectomy, Pitavastatin-NPs still decreased the number of monocytes/macrophages in the infarcted heart and inhibited post-infarct LV remodeling.Nanoparticle-mediated delivery of pitavastatin to monocytes/macrophages may be a novel therapeutic strategy to protect the heart from post-infarct LV remodeling. Inhibition of monocyte mobilization from the bone marrow is one of the major mechanisms by which Pitavastatin-NPs attenuated post-infarct LV remodeling.

A Translational Study of a New Therapeutic Approach for Acute Myocardial Infarction: Nanoparticle-Mediated Delivery of Pitavastatin into Reperfused Myocardium Reduces Ischemia-Reperfusion Injury in a Preclinical Porcine Model.

BACKGROUND: There is an unmet need to develop an innovative cardioprotective modality for acute myocardial infarction, for which interventional reperfusion therapy is hampered by ischemia-reperfusion (IR) injury. We recently reported that bioabsorbable poly(lactic acid/glycolic acid) (PLGA) nanoparticle-mediated treatment with pitavastatin (pitavastatin-NP) exerts a cardioprotective effect in a rat IR injury model by activating the PI3K-Akt pathway and inhibiting inflammation. To obtain preclinical proof-of-concept evidence, in this study, we examined the effect of pitavastatin-NP on myocardial IR injury in conscious and anesthetized pig models. METHODS AND RESULTS: Eighty-four Bama mini-pigs were surgically implanted with a pneumatic cuff occluder at the left circumflex coronary artery (LCx) and telemetry transmitters to continuously monitor electrocardiogram as well as to monitor arterial blood pressure and heart rate. The LCx was occluded for 60 minutes, followed by 24 hours of reperfusion under conscious conditions. Intravenous administration of pitavastatin-NP containing ≥ 8 mg/body of pitavastatin 5 minutes before reperfusion significantly reduced infarct size; by contrast, pitavastatin alone (8 mg/body) showed no therapeutic effects. Pitavastatin-NP produced anti-apoptotic effects on cultured cardiomyocytes in vitro. Cardiac magnetic resonance imaging performed 4 weeks after IR injury revealed that pitavastatin-NP reduced the extent of left ventricle remodeling. Importantly, pitavastatin-NP exerted no significant effects on blood pressure, heart rate, or serum biochemistry. Exploratory examinations in anesthetized pigs showed pharmacokinetic analysis and the effects of pitavastatin-NP on no-reflow phenomenon. CONCLUSIONS: NP-mediated delivery of pitavastatin to IR-injured myocardium exerts cardioprotective effects on IR injury without apparent adverse side effects in a preclinical conscious pig model. Thus, pitavastatin-NP represents a novel therapeutic modality for IR injury in acute myocardial infarction.

Anti-inflammatory Nanoparticle for Prevention of Atherosclerotic Vascular Diseases.

Recent technical innovation has enabled chemical modifications of small materials and various kinds of nanoparticles have been created. In clinical settings, nanoparticle-mediated drug delivery systems have been used in the field of cancer care to deliver therapeutic agents specifically to cancer tissues and to enhance the efficacy of drugs by gradually releasing their contents. In addition, nanotechnology has enabled the visualization of various molecular processes by targeting proteinases or inflammation. Nanoparticles that consist of poly (lactic-co-glycolic) acid (PLGA) deliver therapeutic agents to monocytes/macrophages and function as anti-inflammatory nanoparticles in combination with statins, angiotensin receptor antagonists, or agonists of peroxisome proliferator-activated receptor-γ (PPARγ). PLGA nanoparticle-mediated delivery of pitavastatin has been shown to prevent inflammation and ameliorated features associated with plaque ruptures in hyperlipidemic mice. PLGA nanoparticles were also delivered to tissues with increased vascular permeability and nanoparticles incorporating pitavastatin, injected intramuscularly, were retained in ischemic tissues and induced therapeutic arteriogenesis. This resulted in attenuation of hind limb ischemia. Ex vivo treatment of vein grafts with imatinib nanoparticles before graft implantation has been demonstrated to inhibit lesion development. These results suggest that nanoparticle-mediated drug delivery system can be a promising strategy as a next generation therapy for atherosclerotic vascular diseases.

A New Therapeutic Modality for Acute Myocardial Infarction: Nanoparticle-Mediated Delivery of Pitavastatin Induces Cardioprotection from Ischemia-Reperfusion Injury via Activation of PI3K/Akt Pathway and Anti-Inflammation in a Rat Model.

AIM: There is an unmet need to develop an innovative cardioprotective modality for acute myocardial infarction (AMI), for which the effectiveness of interventional reperfusion therapy is hampered by myocardial ischemia-reperfusion (IR) injury. Pretreatment with statins before ischemia is shown to reduce MI size in animals. However, no benefit was found in animals and patients with AMI when administered at the time of reperfusion, suggesting insufficient drug targeting into the IR myocardium. Here we tested the hypothesis that nanoparticle-mediated targeting of pitavastatin protects the heart from IR injury. METHODS AND RESULTS: In a rat IR model, poly(lactic acid/glycolic acid) (PLGA) nanoparticle incorporating FITC accumulated in the IR myocardium through enhanced vascular permeability, and in CD11b-positive leukocytes in the IR myocardium and peripheral blood after intravenous treatment. Intravenous treatment with PLGA nanoparticle containing pitavastatin (Pitavastatin-NP, 1 mg/kg) at reperfusion reduced MI size after 24 hours and ameliorated left ventricular dysfunction 4-week after reperfusion; by contrast, pitavastatin alone (as high as 10 mg/kg) showed no therapeutic effects. The therapeutic effects of Pitavastatin-NP were blunted by a PI3K inhibitor wortmannin, but not by a mitochondrial permeability transition pore inhibitor cyclosporine A. Pitavastatin-NP induced phosphorylation of Akt and GSK3ß, and inhibited inflammation and cardiomyocyte apoptosis in the IR myocardium. CONCLUSIONS: Nanoparticle-mediated targeting of pitavastatin induced cardioprotection from IR injury by activation of PI3K/Akt pathway and inhibition of inflammation and cardiomyocyte death in this model. This strategy can be developed as an innovative cardioprotective modality that may advance currently unsatisfactory reperfusion therapy for AMI.

Nanoparticle-mediated drug delivery system for cardiovascular disease.

Administration of drugs and other therapeutic agents has been the central strategy of contemporary medicine for cardiovascular disease. The use of a drug delivery system (DDS) is always demanded to enhance the efficacy and safety of therapeutic agents, and improve the signal-to-noise ratio of imaging agents. Nano-scale materials modify in vivo drug kinetics, depending on (patho)physiological mechanisms such as vascular permeability and incorporation by the mononuclear phagocyte system, which constitute 'passive-targeting' properties of nano-DDS. By contrast, an 'active-targeting' strategy employs a specific targeting structure on nano-DDS, which binds to the target molecule that is specific for a certain disease process, such as tumor specific antigens and the induction of adhesion molecules. In this review, we summarize recent studies that applied nano-DDS for the diagnosis and treatment of cardiovascular disease, especially focusing on atherosclerosis and myocardial ischemia-reperfusion (IR) injury. Pathophysiological changes in atherosclerosis and myocardial IR injury are successfully targeted by nano-DDS and preclinical studies in animals showed positive effects of nano-DDS enhancing efficacy and reducing adverse effects. The development of nano-DDS in clinical medicine is keenly being awaited.

Nanoparticle-mediated delivery of pioglitazone enhances therapeutic neovascularization in a murine model of hindlimb ischemia.

OBJECTIVE: Critical limb ischemia is a severe form of peripheral artery disease (PAD) for which neither surgical revascularization nor endovascular therapy nor current medicinal therapy has sufficient therapeutic effects. Peroxisome proliferator activated receptor-γ agonists present angiogenic activity in vitro; however, systemic administration of peroxisome proliferator-activated receptor-γ agonists is hampered by its side effects, including heart failure. Here, we demonstrate that the nanoparticle (NP)-mediated delivery of the peroxisome proliferator activated receptor-γ agonist pioglitazone enhances its therapeutic efficacy on ischemia-induced neovascularization in a murine model. METHODS AND RESULTS: In a nondiabetic murine model of hindlimb ischemia, a single intramuscular injection of pioglitazone-incorporated NP (1 µg/kg) into ischemic muscles significantly improved the blood flow recovery in the ischemic limbs, significantly increasing the number of CD31-positive capillaries and α-smooth muscle actin-positive arterioles. The therapeutic effects of pioglitazone-incorporated NP were diminished by the peroxisome proliferator activated receptor-γ antagonist GW9662 and were not observed in endothelial NO synthase-deficient mice. Pioglitazone-incorporated NP induced endothelial NO synthase phosphorylation, as demonstrated by Western blot analysis, as well as expression of multiple angiogenic growth factors in vivo, including vascular endothelial growth factor-A, vascular endothelial growth factor-B, and fibroblast growth factor-1, as demonstrated by real-time polymerase chain reaction. Intramuscular injection of pioglitazone (1 µg/kg) was ineffective, and oral administration necessitated a >500 µg/kg per day dose to produce therapeutic effects equivalent to those of pioglitazone-incorporated NP. CONCLUSIONS: NP-mediated drug delivery is a novel modality that may enhance the effectiveness of therapeutic neovascularization, surpassing the effectiveness of current treatments for peripheral artery disease with critical limb ischemia.