Continuous inhibition of poly(ADP-ribose) polymerase does not reduce reperfusion injury in isolated rat heart.

Poly(ADP-ribose) polymerase (PARP), an enzyme that is important to the regulation of nuclear function, is activated by DNA strand breakage. In massive DNA damage, PARP is overactivated, exhausting nicotinamide adenine dinucleotide and leading to cell death. Recent studies have succeeded in reducing cellular damage in ischemia/reperfusion by inhibiting PARP. However, PARP plays an important part in the DNA repair system, and its inhibition may be hazardous in certain situations. We compared the short-time inhibition of PARP against continuous inhibition during ischemia/reperfusion using isolated rat hearts. The hearts were reperfused after 21 minutes of ischemia with a bolus injection of 3-aminobenzamide (3-AB) (10 mg/kg) followed by continuous 3-AB infusion (50 µM) for the whole reperfusion period or for the first 6 minutes or without 3-AB. At the end of reperfusion, contractile function, high-energy phosphate content, nicotinamide adenine dinucleotide content, and infarcted area were significantly preserved in the 3-AB 6-minute group. In the 3-AB continuous group, these advantages were not apparent. At the end of reperfusion, PARP cleavage had significantly proceeded in the 3-AB continuous group, indicating initiation of the apoptotic cascade. Thus, continuous PARP inhibition by 3-AB does not reduce reperfusion injury in the isolated rat heart, which may be because of acceleration of apoptosis.

Risk reductions for cardiovascular disease with pravastatin treatment by dyslipidemia phenotype: a post hoc analysis of the MEGA Study.

BACKGROUND: The beneficial effect of statins for cardiovascular disease (CVD) prevention has been well established. However, the effectiveness among different phenotypes of dyslipidemia has not been confirmed. OBJECTIVE: We evaluated the effect of pravastatin on the incidence of CVD in relation to the phenotype of dyslipidemia. METHODS: The MEGA Study evaluated the effect of low-dose pravastatin on primary prevention of CVD in 7832 Japanese patients, who were randomized to diet alone or diet plus pravastatin and followed for more than 5 years. These patients were classified into phenotype IIa (n=5589) and IIb (n=2041) based on the electrophoretic pattern for this post hoc analysis. RESULTS: In the diet group there was no significant difference in the incidence of coronary heart disease (CHD), stroke, CVD, and total mortality between the two phenotypes. Phenotype IIb patients, compared to phenotype IIa, had lower levels of high-density lipoprotein cholesterol (HDL-C) and a significantly higher incidence of CVD in relation to a low HDL-C level (<47.5mg/dL; p=0.02). Furthermore, pravastatin decreased the relative risk for each major endpoint in both type IIa and type IIb dyslipidemia. Significant risk reductions were observed for CHD by 38% (p=0.04) and CVD by 31% (p=0.02) in type IIa dyslipidemia but not in phenotype IIb. CONCLUSION: Pravastatin therapy provided significant risk reductions for CHD and CVD in patients with phenotype IIa dyslipidemia, but not in those with phenotype IIb dyslipidemia.

Impact of low-and high-density lipoprotein cholesterol levels on carotid intima-media thickness differs by smoking status in middle-aged men.

AIM: Cigarette smoking is a strong risk factor for atherosclerotic disease; however, it remains unclear whether the impact of other risk factors differs by smoking status. The aim of this study was to investigate this issue, especially with regard to low-density and high-density lipoprotein (LDL/HDL) levels. METHODS: In total, 448 healthy, middle-aged men (aged 37 to 61) participated in this study. Smoking habits were recorded, carotid intima-media thickness (IMT) was measured by B-mode ultrasound, and serum lipids and other biochemical parameters were determined from fasted blood samples. RESULTS: Among the overall subjects, multivariate regression analyses showed that IMT was significantly associated with age (p < 0.0001 for mean IMT, p= 0.002 for max IMT), body mass index (BMI, mean IMT, p= 0.028), LDL-C levels (mean/max IMT, p= 0.001), HDL-C levels (max IMT, p= 0.022) and current smoking habit (mean IMT, p=0.012). Subgroup analyses according to smoking status revealed that LDL-C levels were significantly associated with mean/max IMT in current smokers (p=0.001) but not in ex- or nonsmokers (never smoked subjects). After adjusting for age, BMI, systolic blood pressure, hemoglobin A1c and serum lipids, mean IMT respectively increased and decreased progressively across LDL-C and HDL-C quartiles (p= 0.004 and 0.045) in the overall subjects. These associations were observed in current smokers (p= 0.01) but not in ex- or nonsmokers for LDL-C, and were observed in ex- and nonsmokers (p= 0.025, 0.017, respectively) but not in current smokers for HDL-C. CONCLUSION: The impact of LDL-C/HDL-C levels on carotid IMT differs by smoking status. These observations imply that distinct mechanisms are involved in the (anti) atherogenesis of LDL/HDL according to smoking status.

Statin inhibits hypoxia-induced endothelin-1 via accelerated degradation of HIF-1α in vascular smooth muscle cells.

AIMS: Endothelin-1 (ET-1) contributes to the pathogenesis of cardiovascular diseases with multiple properties such as vasoconstriction. Human ET-1 gene expression is up-regulated by the transcription factor hypoxia-inducible factor-1 (HIF-1) through hypoxia response element (HRE). Although previous studies suggested that 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors (statins) alter HIF-1-related gene expression, it remained unclear whether statins modulate HIF-1-mediated ET-1 expression. Therefore, we investigated the effect of fluvastatin on hypoxia-induced human ET-1 expression in vascular smooth muscle cells (VSMC). METHODS AND RESULTS: Hypoxia (1% O(2)), compared with the normoxic condition (21% O(2)), significantly induced the expression of preproET-1 mRNA, ET-1 protein, and ET-1 secretion in VSMC. Hypoxia induced a 2.3-fold increase in HRE-dependent ET-1 reporter gene activation. Under concentrations of 1 µmol/L or greater, fluvastatin attenuated the hypoxia-induced ET-1 gene expression through the accelerated ubiquitin/proteasome-dependent degradation of HIF-1α, thus consequently attenuating HIF-1α binding to the HRE of the ET-1 gene. These inhibitory effects of fluvastatin were cancelled by concomitant treatment with mevalonate, farnesyl pyrophosphate, or geranylgeranyl pyrophosphate, but not squalene. CONCLUSION: The present study suggests that fluvastatin attenuates HIF-1-dependent ET-1 gene expression in conjunction with the stimulation of HIF-1α ubiquitin/proteasome-dependent degradation via isoprenoid-dependent mechanisms.

Associations between serum lipoprotein(a) levels and the severity of coronary and aortic atherosclerosis.

To elucidate the associations between Lp(a) levels and coronary and aortic atherosclerosis, we performed aortic MRI in 143 patients undergoing coronary angiography. Severity of aortic atherosclerosis was represented as plaque scores. Of the 143 patients, 104 had coronary artery disease (CAD). Thoracic and abdominal aortic plaques were found in 89 and 131 patients. Lp(a) levels increased stepwise with the number of stenotic coronary vessels: 15.7 (CAD(-)), 21.2 (1-vessel), 21.4 (2-vessel), and 22.9 mg/dl (3-vessel) (P<0.05). For aortic atherosclerosis, 143 patients were divided into quartiles by plaque scores. Lp(a) did not differ among quartiles of thoracic plaques: 17.1, 19.0, 23.5, and 21.2 mg/dl (P=NS), whereas Lp(a) increased stepwise with quartiles of abdominal plaques: 17.1, 19.2, 19.1, and 24.0 mg/dl (P<0.05). Lp(a) was an independent factor for CAD and abdominal aortic plaques, but not thoracic plaques. Thus, Lp(a) levels were associated with aortic atherosclerosis, especially in abdominal aorta, as well as coronary atherosclerosis.

Deficiency of interleukin-1 receptor antagonist promotes spontaneous femoral artery aneurysm formation in mice.

Femoral artery aneurysms (FAAs) are very rare, and their natural history is not well understood. In this study, we sought to analyze the pathogenesis of inflammatory FAAs in interleukin-1 receptor antagonist-deficient (IL-1Ra(-/-)) B6 mice. Systolic arterial pressures and plasma lipid levels of IL-1Ra(-/-) mice and wild-type (WT) mice did not differ significantly. However, IL-1Ra(-/-) mice spontaneously developed fusiform FAAs. Real-time PCR of 9-month-old IL-1Ra(-/-) mice revealed significantly increased mRNA levels of IL-1ß (6.6-fold), tumor necrosis factor-α (TNF-α) (12.4-fold), and matrix metalloproteinase-9 (6.0-fold) compared with WT mice. Histological analysis revealed numerous inflammatory cells around the FAAs in IL-1Ra(-/-) mice, and elastin staining showed destruction of both the internal and external elastic lamina in IL-1Ra(-/-) mice. Afterward, macrophage function was studied. After lipopolysaccharide (1 µg/mL) stimulation, IL-1Ra-deficient macrophages produced much higher levels of TNF-α than those from WT mice. Finally, we performed bone marrow cell transplantation. FAAs with many inflammatory cells in the adventitia were detected in several WT mice that received bone marrow cells from IL-1Ra(-/-) mice (44%), but not from WT mice (0%). Our study is the first to demonstrate that IL-1Ra deficiency in inflammatory cells disrupts immune system homeostasis and induces inflammatory FAAs in IL-1Ra(-/-) B6 mice. We believe that these mice will provide much information about the natural history and management of FAAs.

IκBNS regulates interleukin-6 production and inhibits neointimal formation after vascular injury in mice.

AIMS: IκBNS regulates a subset of Toll-like receptor (TLR)-dependent genes including interleukin-6 (IL-6) by inhibiting nuclear factor-κB (NF-κB). IL-6 is an inflammatory biomarker for cardiovascular diseases. The aim of this study was to determine whether IκBNS changes arterial inflammation and intimal hyperplasia after vascular injury. METHODS AND RESULTS: We investigated neointimal formation in IκBNS-deficient (IκBNS(-/-); C57BL/6 background) and wild-type (IκBNS(+/+)) mice 2 weeks after cuff injury. The mean intimal area and the intima/media ratio of IκBNS(-/-) mice increased 89% (8066 ± 1141 vs. 4267 ± 1095 µm(2); P = 0.027) and 100% (0.72 ± 0.13 vs. 0.36 ± 0.09; P = 0.032) compared with IκBNS(+/+) mice. We observed significant up-regulation of TLR4 in injured arteries of IκBNS(-/-) mice. NF-κB activity in the intima of IκBNS(-/-) mice was 5.1-fold higher (P = 0.008) compared with IκBNS(+/+) mice at 7 days post-injury. IL-6 mRNA levels in injured arteries of IκBNS(-/-) mice were 1.8-fold higher (P = 0.002) compared with those of IκBNS(+/+) mice at 3 days post-injury. Vascular smooth muscle cells from IκBNS(-/-) mice showed a significant increase in cell migration compared with those from IκBNS(+/+) mice after IL-6 stimulation in the scratch-wound healing assay. Furthermore, anti-mouse IL-6 receptor antibody (MR16-1) significantly reduced intimal hyperplasia compared with control IgG injection in IκBNS(-/-) mice. These findings suggest that IL-6 participates in the development of neointimal hyperplasia after vascular injury in IκBNS(-/-) mice. CONCLUSION: IκBNS down-regulates TLR4 expression, NF-κB activity, and IL-6 production after vascular injury. IκBNS might suppress intimal hyperplasia caused by vascular inflammation such as atherosclerosis, and restenosis after angioplasty.

Novel TNF-α receptor 1 antagonist treatment attenuates arterial inflammation and intimal hyperplasia in mice.

AIM: Tumor necrosis factor receptor 1 (TNFR1) participates importantly in arterial inflammation in genetically altered mice; however it remains undetermined whether a selective TNFR1 antagonist inhibits arterial inflammation and intimal hyperplasia. This study aimed to determine the effect and mechanism of a novel TNFR1 antagonist in the suppression of arterial inflammation. METHODS: We investigated intimal hyperplasia in IL-1 receptor antagonist-deficient mice two weeks after inducing femoral artery injury in an external vascular cuff model. All mice received intraperitoneal injections of TNFR1 antagonist (PEG-R1antTNF) or normal saline twice daily for 14 days. RESULTS: PEG-R1antTNF treatment yielded no adverse systemic effects, and we observed no significant differences in serum cholesterol or blood pressure in either group; however, selective PEG-R1antTNF treatment significantly reduced intimal hyperplasia (19,671±4,274 vs. 11,440±3,292 µm(2); p=0.001) and the intima/media ratio (1.86±0.43 vs. 1.34±0.36; p=0.029), compared with saline injection. Immunostaining revealed that PEG-R1antTNF inhibits Nuclear factor-κB (NF-κB), suppressing smooth muscle cell (SMC) proliferation and decreasing chemokine and adhesion molecule expression, and thus decreasing intimal hyperplasia and inflammation. CONCLUSIONS: Our data suggest that PEG-R1antTNF suppresses SMC proliferation and inflammation by inhibiting NF-κB. This study highlights the potential therapeutic benefit of selective TNFR1 antagonist therapy in preventing intimal hyperplasia and arterial inflammation.

Deficiency of CuZn superoxide dismutase promotes inflammation and alters medial structure following vascular injury.

AIM: The anti-oxidant enzyme copper/zinc superoxide dismutase (CuZnSOD) metabolizes superoxide anion (O(2)(-)) in vascular cells. However, the role of CuZnSOD in vascular injury remains poorly understood. METHODS: Using CuZnSOD-deficient (CuZnSOD(-/-)) mice and wild-type (WT) mice, we investigated morphometric changes and the role of O(2)(-) in vascular remodeling after femoral artery injury induced by an external vascular cuff model. RESULTS: Three days post-injury, inflammatory cell infiltration increased significantly. Moreover, the percent positive area of tumor necrosis factor-α (TNF-α), intercellular adhesion molecule-1 (ICAM-1), and vascular cell adhesion molecule-1 (VCAM-1) in media were higher in CuZnSOD(-/-) mice than in WT mice (TNF-α: 34.8±8.4% versus 18.8±5.6%, p < 0.05, ICAM-1: 29.6±6.5% versus 11.0±2.8%, p < 0.05, VCAM-1: 23.5±7.5% versus 3.7±1.1%, p < 0.05). mRNA expression of iNOS was markedly increased in CuZnSOD(-/-) mice with cuff injury. Dihydroethidine staining revealed increased levels of vascular O(2)(-) in media from CuZnSOD(-/-) mice. Although neointimal formation remained unchanged, 14 days postinjury, we observed degeneration of the media, and the media/vessel wall ratio increased in CuZnSOD(-/-) mice (40.4±2.1% versus 26.8±1.4%, p < 0.05). Furthermore, SMemb/MHC-B-stained lesions increased markedly in CuZnSOD(-/-) mice. CONCLUSIONS: CuZnSOD-deficiency promoted inflammation, expressed adhesion molecules, and altered the structure of the media post-injury. Our results suggest that O(2)(-) participates importantly in the progression of early stage vascular inflammation, resulting in vascular remodeling in media but not neointimal formation, post-injury.

Proteasomal inhibition promotes ATP-binding cassette transporter A1 (ABCA1) and ABCG1 expression and cholesterol efflux from macrophages in vitro and in vivo.

OBJECTIVE: ATP-binding cassette transporter A1 (ABCA1) and ABCG1 are key molecules in an initial step of reverse cholesterol transport (RCT), a major antiatherogenic property of high-density lipoprotein (HDL). The ubiquitin-proteasome system (UPS) mediates nonlysosomal pathways for protein degradation and is known to be involved in atherosclerosis. However, little is known about the effects of the UPS on these molecules and overall RCT. We therefore investigated whether UPS inhibition affects ABCA1/G1 expression in macrophages and RCT in vitro and in vivo. METHODS AND RESULTS: Various proteasome inhibitors increased ABCA1/G1 expression in macrophages, translating into enhanced apolipoprotein A-I- and HDL-mediated cholesterol efflux from macrophages. ABCA1 and ABCG1 were found to undergo polyubiquitination in the macrophages and HEK293 cells overexpressing these proteins, and pulse-chase analysis revealed that proteasome inhibitors inhibited ABCA1/G1 protein degradation. In in vivo experiments, the proteasome inhibitor bortezomib increased ABCA1/G1 protein levels in mouse peritoneal macrophages, and RCT assays showed that it significantly increased the fecal (54% increase compared with saline) and plasma (23%) appearances of the tracer derived from intraperitoneally injected (3)H-cholesterol-labeled macrophages. CONCLUSIONS: The present study provided evidence that the UPS is involved in ABCA1/G1 degradation, thereby affecting RCT in vivo. Therefore, specific inhibition of the UPS pathway might lead to a novel HDL therapy that enhances RCT.

Pulmonary intravascular lymphoma diagnosed by 18-fluorodeoxyglucose positron emission tomography-guided transbronchial lung biopsy in a man with long-term survival: a case report.

INTRODUCTION: 18-Fluorodeoxyglucose positron emission tomography can detect the pulmonary involvement of intravascular lymphoma that presents no abnormality in a computed tomography scan. CASE PRESENTATION: We report the case of a 61-year-old Japanese man who had pulmonary intravascular lymphoma and no computed tomography abnormality. We were able to make an antemortem diagnosis of pulmonary intravascular lymphoma by transbronchial lung biopsy according to 18-fluorodeoxyglucose positron emission tomography findings. He is free of recurrent disease 24 months after chemotherapy. CONCLUSIONS: To the best of our knowledge, this is the first reported case of a long-term survivor of pulmonary intravascular lymphoma diagnosed by transbronchial lung biopsy under the guide of 18-fluorodeoxyglucose positron emission tomography.

Hemoglobin vesicle improves recovery of cardiac function after ischemia-reperfusion by attenuating oxidative stress in isolated rat hearts.

Hemoglobin vesicle (HbV) could be a useful blood substitute in emergency medicine. The aim of this study was to clarify the effects of HbV on cardiac function after ischemia-reperfusion (I/R) ex vivo. Isolated rat hearts were perfused according to the Langendorff method. An ischemia-reperfusion group (n = 6) was subjected to 25 minutes of global ischemia and 30 minutes of reperfusion. HbV (hemoglobin, 0.33 g/dL) was perfused before ischemia-reperfusion for 10 minutes (HbV group, n = 6). Hemodynamics were monitored, and tissue glutathione contents were measured. The redox state of reactive thiols in cardiac tissues was assessed by the biotinylated iodoacetamide labeling method. Left ventricular developed pressure was significantly recovered in the HbV group after 30 minutes of reperfusion (56.3 ± 2.8 mm Hg vs. ischemia-reperfusion group 27.0 ± 8.0 mm Hg, P < 0.05). Hemodynamic changes induced by HbV were similar to those observed when N-nitro-L-arginine methyl ester was perfused for 10 minutes before ischemia-reperfusion (L-NAME group). The oxidized glutathione contents of cardiac tissues significantly decreased, and biotinylated iodoacetamide labeling of thiols was maintained in both the HbV and the L-NAME groups. HbV improved the recovery of cardiac function after ischemia-reperfusion in isolated rat hearts. This mechanism is dependent on functional protection against thiol oxidation.

Olmesartan improves endothelial function in hypertensive patients: link with extracellular superoxide dismutase.

Endothelial dysfunction in essential hypertension is an independent predictor for future cardiovascular events. Although inhibition of the renin-angiotensin system (RAS) reportedly improves endothelial function through its effects on oxidative stress and inflammation, questions remain regarding the factors that are pivotal for improvement of endothelial function by RAS inhibition. We therefore performed a prospective, randomized crossover trial in which an angiotensin II type 1 receptor antagonist, olmesartan and calcium channel blocker, amlodipine, were compared in 31 essential hypertensive patients. Results showed that, although both treatments achieved comparable lowering of blood pressure (BP), olmesartan, but not amlodipine, significantly improved endothelial function as evaluated by flow-mediated vasodilation (FMD) in the brachial artery. Although no significant changes in diabetic and lipid parameters were observed with either drug, olmesartan slightly decreased estimated glomerular filtration rate, which, surprisingly, translated into decreased microalbuminuria. In a similar vein, olmesartan reduced serum C-reactive protein and increased urine antioxidant levels compared with baseline, and reduced urine 8-epi-prostaglandin F2α levels compared with both baseline and amlodipine. Finally, although overall changes in plasma extracellular superoxide dismutase (EC-SOD) levels were not modulated by either treatment, for olmesartan there was a positive correlation between changes in FMD and those in EC-SOD levels. In conclusion, olmesartan improved endothelial function in hypertensive patients independent of its BP-lowering effect, which was due, at least in part, to its antioxidative property. Therefore, olmesartan might provide a greater long-term benefit for hypertensive patients with impaired endothelial function than amlodipine.

A case of idiopathic dilatation of the pulmonary artery with mild subvalvular pulmonary stenosis revealed by cardiovascular magnetic resonance.

We present herein a rare case of idiopathic pulmonary artery dilatation with mild subvalvular pulmonary stenosis. The chest radiograph showed the protrusion of the left second arch of the cardiac silhouette. Cardiovascular magnetic resonance revealed an aneurysmal pulmonary trunk (maximal diameter, 4.5 cm) and mild subvalvular pulmonary stenosis. The pressure gradient across the pulmonary valve was mild (peak-to-peak, 11 mmHg), and the right ventricular pressure was normal. We diagnosed this case with idiopathic dilatation of the pulmonary artery by excluding other causes of pulmonary arterial enlargement.

Serum resistin levels and cardiovascular events in patients undergoing percutaneous coronary intervention.

AIM: Resistin is an adipocytokine that may link inflammation and atherosclerosis.We studied the associations of resistin levels with cardiovascular events and restenosis. METHODS: We measured pre-procedural serum resistin levels in 140 patients with coronary artery disease undergoing elective percutaneous coronary intervention (PCI), of whom 97 had a stent. Restenosis was defined as > 50% stenosis at follow-up angiography. Patients were followed for 3 years for major adverse cardiovascular events (MACE). RESULTS: At 8±6 months after PCI, reangiography was performed in 94 (67%) patients, of whom 42 had restenosis. Between 42 patients with restenosis and 52 without restenosis, resistin (4.5±2.6 vs. 4.5±2.5 ng/mL) and Creactive protein (CRP) (median 0.70 vs. 0.70 mg/L) levels did not differ. During 3-year follow-up, MACE occurred in 24 patients (1 death, 21 unstable angina, 2 stroke). Compared with 116 patients without MACE, 24 with MACE had higher resistin (5.4±2.4 vs. 4.3±2.5 ng/mL) and CRP (1.30 vs. 0.60 mg/L) levels (p< 0.05). Patients with MACE more often had resistin >4.0 ng/mL than without MACE (75% vs. 35%, p< 0.001). Resistin correlated with CRP levels (r= 0.31). To clarify the association between MACE and resistin, patients were divided into 2 groups by resistin levels. Kaplan-Meier analysis showed a lower event-free survival rate in patients with resistin > 4.0 ng/mL than without it (p< 0.001). On multivariate analysis, resistin, but not CRP, was an independent predictor of MACE. The hazard ratio for MACE was 3.6 (95%CI=1.4-9.2) for resistin > 4.0 ng/mL. CONCLUSION: Serum resistin levels were found to be associated with further cardiovascular events in patients undergoing PCI.

Enhancement of ultrasonic thrombus imaging using novel liposomal bubbles targeting activated platelet glycoprotein IIb/IIIa complex--in vitro and in vivo study.

BACKGROUND: We developed perfluorocarbon gas-containing bubble liposomes (BL) with Arg-Gly-Asp (RGD) sequence-containing peptides, which bind to activated platelet glycoprotein IIb/IIIa complexes. The aim of this study was to examine the enhancing effects in ultrasonic thrombus imaging using these targeted BL in vitro and in vivo. METHODS: Liposomes composed of phosphatidylcholine and cholesterol were manufactured, and RGD peptide was attached by a covalent coupling reaction. Sonication was used to conjugate liposomes and perfluorocarbon gas, which formed targeted BL. In vitro, targeted BL were mixed with whole blood, which was allowed to coagulate while being shaken and rotated. In vivo, we administered targeted BL to 10 rabbits with acute thrombotic occlusions in the ilio-femoral artery. Thrombi were imaged using a 7.5-9 MHz linear transducer and a conventional ultrasound machine, and by scanning electron microscopy. Ultrasound images were digitized, and mean pixel gray-scale level (black = 0, white = 255) was measured. RESULTS: In vitro, mean pixel gray-scale level of the thrombi in targeted BL group was significantly higher than in control and non-targeted BL groups (93 ± 26 vs. 58 ± 16, 48 ± 9, p = 0.002, n = 10). Scanning electron microscopy revealed large amounts of targeted BL attached to the thrombi. In vivo, mean pixel gray-scale level of the thrombi with targeted BL was significantly higher (33.2 ± 6.4 vs. 24.8 ± 8.5, p = 0.0051, n = 10) than that before targeted BL administration. CONCLUSIONS: Perfluorocarbon gas-containing BL with RGD peptide represent a novel echo contrast agent, which can markedly enhance ultrasonic thrombus imaging in vitro and in vivo, and may be useful for noninvasively diagnosing acute thrombotic vessel occlusion.

Cilostazol enhances macrophage reverse cholesterol transport in vitro and in vivo.

OBJECTIVE: Recent failure of an HDL-cholesterol raising strategy using a cholesteryl ester transfer protein inhibitor highlights the importance of the anti-atherogenic function rather than plasma concentration of HDL. Cilostazol, a selective inhibitor of phosphodiesterase 3, has been widely used in patients with atherosclerotic diseases and is known to increase HDL-cholesterol. However, it remains unclear whether cilostazol enhances anti-atherogenic properties by promoting reverse cholesterol transport (RCT), a major anti-atherogenic function of HDL. METHODS AND RESULTS: We observed that treatment of THP-1 macrophages, human monocyte-derived macrophages, and RAW264.7 cells with cilostazol increased ABCA1 and ABCG1 expression in a concentration-dependent manner, translating into enhanced apoA-I- and HDL-mediated cholesterol efflux from the macrophages. However, other cyclic AMP (cAMP)-elevating agents did not increase ABCA1 gene expression in THP-1 macrophages. Cilostazol did not change intracellular cAMP levels in THP-1 macrophages and RAW264.7 cells, and a protein kinase A (PKA) inhibitor did not affect cilostazol-induced ABCA1 and ABCG1 expression. To further investigate RCT in vivo, (3)H-cholesterol-labeled and acetyl LDL-loaded RAW264.7 cells were intraperitoneally injected into mice and the appearance of the (3)H-tracer was monitored in plasma, liver, and feces. Supporting the in vitro data, cilostazol was found to significantly increase (3)H-tracer levels in both plasma and feces. CONCLUSIONS: These findings indicate that cilostazol might provide anti-atherosclerotic effects by promoting RCT through increased ABCA1/G1 expression in macrophages.

Severe, short-term food restriction improves cardiac function following ischemia/reperfusion in perfused rat hearts.

The purpose of this study was to clarify the characteristics of improved ischemic tolerance induced by severe, short-term food restriction in isolated, perfused rat hearts. Male Wistar (8 week-old) rats were given a food intake equivalent to a 70% reduction on the food intake of ad-libitum fed rats for 11 days (FR group and AL group, respectively). After this period, hearts were isolated and perfused in the Langendorff mode, and subjected to 20 min of global ischemia followed by 30 min of reperfusion. Although the coronary flow rate in the FR group (63.0 +/- 3.1 ml/min/g dry weight) was higher than that in the AL group (47.1 +/- 1.3 ml/min/g dry weight) during preischemic perfusion, the lactate release into the coronary effluent and absolute values of +dP/dt and -dP/dt in the FR group (2422 +/- 161 and -1282 +/- 51) were inversely lower than in the AL group (2971 +/- 156 and -1538 +/- 74, respectively). An increase in ischemic contracture was suppressed in the FR group. Following reperfusion, cardiac function, high-energy phosphate content, and intracellular pH, as measured by 31P-nuclear magnetic resonance spectroscopy, had recovered to a much greater degree in the FR group than in the AL group. The serum T3 level was significantly lower in the FR group (2.7 +/- 0.1 pg/ml) than in the AL group (3.6 +/- 0.1 pg/ml), and the levels of triglycerides, free fatty acids, insulin, and glucose were also significantly lower in the FR group than in the AL group. The protein expressions of myocyte enhancer factor 2A, Na(+), K(+)-ATPase, and phospholamban in the cardiac tissue were higher in the FR group than in the AL group. These results suggested that severe, short-term food restriction improves ischemic tolerance in rat hearts via altered expression of functional proteins induced by low serum T3 levels, decreased coronary conductance, and change in metabolic flux.