bluuebunny/crossref_metadata_2025 huggingface dataset:
Inhibition of Type 4 Phosphodiesterase by Rolipram and
Ginkgo biloba
Extract (EGb 761) Decreases Agonist-Induced Rises in Internal Calcium in Human Endothelial Cells
Authors: Campos-Toimil Manuel , Lugnier Claire , Droy-Lefaix Marie-Thérèse , Takeda Kenneth
Published: June 2011

Abstract
—The effects of
Gingko biloba
extract EGb 761 on 5 isolated, vascular, cyclic nucleotide phosphodiesterase (PDE) isoforms were evaluated. EGb 761 preferentially inhibited PDE4 (IC
50
=25.1 mg/L), the isoform that is mainly present in endothelial cells, in a competitive manner (
K
i
=12.5 mg/L). Because changes in cyclic nucleotide levels may affect intracellular calcium ([Ca
2+
]
i
) levels in endothelial cells, we examined the effects of EGb 761 on both resting [Ca
2+
]
i
levels and agonist-induced rises in [Ca
2+
]
i
in single human umbilical vein endothelial cells (HUVECs) in culture. The effects of EGb 761 were compared with those of rolipram, a selective PDE4 inhibitor that increases cellular cAMP levels, and the cAMP analogue dibutyryl cAMP (db-cAMP). EGb 761 (20 and 100 mg/L), rolipram (50 μmol/L), and db-cAMP (100 μmol/L) significantly inhibited histamine-, ATP-, and thrombin-induced [Ca
2+
]
i
increases in HUVECs without modifying resting [Ca
2+
]
i
levels. Similar results were obtained by using a Ca
2+
-free bath solution. EGb 761 (100 mg/L), but not rolipram (50 μmol/L) or db-cAMP (100 μmol/L), also inhibited Ca
2+
influx into cells having thapsigargin-depleted internal Ca
2+
stores and bathed in a Ca
2+
-free external solution. Our results are consistent with an inhibition of PDE activity that causes a reduction of agonist-induced increases in [Ca
2+
]
i
in HUVECs, mainly by inhibition of Ca
2+
mobilization from internal stores. It thus may be that the cardiovascular effects of EGb 761 involve inhibition of PDE4 activity and subsequent modification of Ca
2+
signaling in endothelial cells.
Antibodies to Oxidized LDL in Relation to Intima-Media Thickness in Carotid and Femoral Arteries in 58-Year-Old Subjectively Clinically Healthy Men
Authors: Hulthe Johannes , Bokemark Lena , Fagerberg Björn
Published: June 2011

Abstract
—Antibody (Ab) titers to oxidized low density lipoprotein (OxLDL) have been found to be independent predictors of the progression of carotid atherosclerosis. Ab titers against OxLDL may be related to the entire burden of atherosclerosis in the vascular tree or, more specifically, to the disease process in different arterial regions. Therefore, the aim of the present study was to investigate the relationship between IgG and IgM titers to modified LDL and intima-media thickness (IMT) in the carotid and femoral arteries in subjectively clinically healthy 58-year-old men. IMT was measured by ultrasound, and Ab titers to modified LDL were measured by ELISA. The results showed that the common carotid artery IMT was associated with elevated titers of IgG-OxLDL Ab and independently with systolic blood pressure, smoking, and body mass index. The femoral artery IMT showed a negative correlation to IgM-OxLDL Ab and independent associations with smoking, systolic blood pressure, and total cholesterol. To summarize, in 58-year-old subjectively clinically healthy men recruited from the general population, there was a positive association between IgG-OxLDL Ab and IMT in the common carotid artery and a negative association between IgM-OxLDL Ab and IMT in the common femoral artery. However, these associations were not independent of other risk factors.
Shear Stress Decreases Endothelial Cell Tissue Factor Activity by Augmenting Secretion of Tissue Factor Pathway Inhibitor
Authors: Grabowski Eric F. , Reininger Armin J. , Petteruti Philip G. , Tsukurov Olga , Orkin Roslyn W.
Published: June 2011

Abstract
—Monolayers of human umbilical vein endothelial cells were activated with 50 U/mL interleukin-1α (IL-1α) for 3 hours and simultaneously conditioned with shear stresses of 0, 0.68, or 13.2 dyne/cm
2
in a parallel-plate flow chamber. In the presence of an inflow buffer containing 100 nmol/L factor X and 10 nmol/L factor VII, production of factor Xa, a measure of functional tissue factor (TF), was determined as the product of outflow concentration of factor Xa (chromogenic assay performed under quasi-static flow conditions after the shear period) and flow rate. Similarly, production of TF pathway inhibitor (TFPI) was estimated as the product of antigenic TFPI (by enzyme-linked immunosorbent assay) in the supernatant and flow rate. In parallel experiments, total RNA was isolated for determination of amplification products of TF mRNA by reverse transcription–polymerase chain reaction. We found that shear stress reduced factor Xa production (mean±SE; n=number of experiments) from 13.33±1.14 (n=16) fmol/min×cm
2
at 0 shear stress to 5.70±2.51 (n=5) and 0.54±0.54 (n=4) fmol/min×cm
2
at shear stresses of 0.68 and 13.2 dyne/cm
2
, respectively. At the same time, immunogold labeling showed that TF antigen on the endothelial surface increased >5-fold with shear stress, whereas TFPI antigen on the surface increased 2-fold. The secretion of TFPI (appearance of new supernatant TFPI) rose from 7.4±2.4 (n=12) ×10
−
3
fmol/min×cm
2
at 0 shear stress to 23.7±7.3 (n=9) and 50.2±14.3 (n=4) ×10
−
3
fmol/min×cm
2
at 0.68 and 13.2 dyne/cm
2
, respectively. TF mRNA amplification products were not markedly changed by shear stress. We conclude that acute application of shear stress reduces functional, but not antigenic, expression of TF by intact, activated endothelial cell monolayers in a manner associated with shear stress–augmented endothelial cell secretion of TFPI.
Endogenous Nitric Oxide and Prostaglandins Synergistically Counteract Thromboembolism in Arterioles but Not in Venules
Authors: Broeders Martijn A. W. , Tangelder Geert-Jan , Slaaf Dick W. , Reneman Robert S. , Egbrink Mirjam G. A. oude
Published: June 2011

Abstract
—It has been shown that NO and prostacyclin (prostaglandin I
2
) from cultured endothelium synergistically inhibit blood platelet aggregation in vitro. However, it is unknown whether this synergism is also effective in the inhibition of thromboembolism in vivo and, if it is, whether it differs between vessel types. Therefore, the effect of endogenous NO and prostacyclin, in combination or alone, on thromboembolism was studied in an in vivo model. Thromboembolism was induced by micropipette puncture of rabbit mesenteric arterioles and venules (diameter 18 to 40 μm). In addition, the influence of wall shear rate was analyzed. In arterioles, the combined inhibition of NO synthase (
N
G
-nitro-
l
-arginine [L-NA] 0.1 mmol/L; local superfusion) and of cyclooxygenase (aspirin [ASA] 100 mg/kg IV) resulted in a pronounced, significant prolongation of embolization duration (median >600 seconds) compared with control (median 153 seconds) or treatment with either L-NA (234 seconds) or ASA (314 seconds). This combined effect of L-NA+ASA was greater than the sum of the individual effects of L-NA and ASA. In contrast, in venules L-NA+ASA had no additional effect on embolization duration (209 seconds) compared with the effect of L-NA alone (230 seconds); ASA alone had no effect (122 seconds; control 72 seconds). Interestingly, only in the L-NA+ASA arterioles did embolization correlate positively with wall shear rate (r
s
=0.687;
P
=0.028). In conclusion, this study indicates that in arterioles, but not in venules, endogenous NO and prostaglandins synergistically counteract ongoing thromboembolism after vessel wall injury and that the combination of endogenous NO and prostaglandins appears to protect against enhancement of arteriolar thromboembolism by wall shear rate.
Cartilage Oligomeric Matrix Protein (Thrombospondin-5) Is Expressed by Human Vascular Smooth Muscle Cells
Authors: Riessen Reimer , Fenchel Michael , Chen Hui , Axel Dorothea I. , Karsch Karl R. , Lawler Jack
Published: June 2011

Abstract
—Cartilage oligomeric matrix protein (COMP/thrombospondin [TSP]-5) belongs to the thrombospondin gene family and is an extracellular glycoprotein found predominantly in cartilage and tendon. To date, there is limited evidence of COMP/TSP-5 expression outside of the skeletal system. The aim of the present study was to investigate the expression of COMP/TSP-5 in cultured human vascular smooth muscle cells and human arteries. COMP/TSP-5 mRNA and protein expression was detected in cultured human vascular smooth muscle cells with both Northern blotting and immunoprecipitation. Serum, as well as transforming growth factor (TGF)-β1 and TGF-β3, stimulated COMP/TSP-5 mRNA expression. COMP/TSP-5 was detected in normal as well as atherosclerotic and restenotic human arteries with immunohistochemistry. The majority of COMP/TSP-5 was expressed in close proximity to vascular smooth muscle cells. In vitro attachment assays demonstrated strong adhesion of smooth muscle cells to COMP/TSP-5–coated surfaces, with the majority of cells spreading and forming stress fibers. In addition, COMP/TSP-5 supported the migration of smooth muscle cells in vitro. The present study shows that COMP/TSP-5 is present in human arteries and may play a role in the adhesion and migration of vascular smooth muscle cells during vasculogenesis and in vascular disease settings such as atherosclerosis.
8-Iso-PGF
2α
Induces β
2
-Integrin–Mediated Rapid Adhesion of Human Polymorphonuclear Neutrophils
Authors: Fontana Luigi , Giagulli Cinzia , Minuz Pietro , Lechi Alessandro , Laudanna Carlo
Published: June 2011

Abstract
—F
2
-Isoprostanes are generated from a cyclooxygenase-independent oxidative modification of arachidonic acid. They are present in atherosclerotic plaques and are platelet activators as well as potent vasoconstrictors. Polymorphonuclear neutrophils are major players in ischemia/reperfusion injury and in restenosis after PTCA. The effects of 8-isoprostaglandin (PG) F
2α
on very rapid β
2
-integrin–dependent adhesion was evaluated in human neutrophils in vitro by use of purified integrin as ligand. 8-Iso-PGF
2α
(1 nmol/L to 20 μmol/L) triggers a dose-dependent, very rapid neutrophil adhesion to human fibrinogen but not to the endothelial ligand intercellular adhesion molecule-1. Pretreatment with anti–β
2
-integrin subtypes showed activation of CD11b/CD18 and CD11c/CD18. Adhesion triggering was completely prevented by pertussis toxin. SQ29,548, a specific antagonist of thromboxane A2 receptor, also dose-dependently prevented 8-iso-PGF
2α
–triggered neutrophil adhesion. 8-Iso-PGF
2α
did not trigger adhesion in human monocytes and lymphocytes and did not induce neutrophil chemotaxis or activation of the oxygen free-radical–forming enzyme NADPH-oxidase. These data highlight the role of 8-iso-PGF
2α
as a specific activator of rapid neutrophil adhesion and suggest its involvement in the pathogenesis of ischemia/reperfusion injury and in restenosis after PTCA. The effect is transduced via activation of the receptor for thromboxane A2.
Endothelial Dysfunction and Denudation in Rat Aortic Allografts
Authors: Andriambeloson Emile , Bigaud Marc , Schraa Edo O. , Kobel Tanja , Lobstein Valerie , Pally Charles , Hans-Günter Zerwes
Published: June 2011

Abstract
—Clinical evidence suggests that early endothelial cell (EC) dysfunction may predict the development of graft vascular disease. We wished to assess the early functional and morphological changes in the graft endothelium in a commonly used animal model of graft vascular disease, the rat aortic interposition allograft model. To assess graft EC function, regulation of vascular tone by ECs was monitored in aortic rings from grafts harvested at various times after transplantation (Tx). EC morphology was assessed by silver staining, which was followed by en face inspection of the luminal side of the grafts. Acetylcholine-induced EC-dependent vasorelaxation was reduced in allografts at post-Tx days 7 and 14, whereas in syngeneic grafts EC-dependent relaxation was unaffected at any time after Tx. In separate grafts collected at the same time points, massive leukocyte adhesion at post-Tx day 7 and EC denudation at days 14 and 28 were evident in allografts but not in syngeneic grafts. At post-Tx day 56 (a time at which vessel wall remodeling is pronounced in this model), an intact EC layer covered the grafts. EC dysfunction and morphological changes were prevented by immunosuppression of recipient rats with cyclosporine. Our study shows that Tx-induced EC dysfunction in rat aortic allografts can be observed within 1 week of Tx in rat aortic allografts and that this is occurring concomitantly with enhanced leukocyte adhesion to the graft ECs. These changes occur before any other morphological or functional changes described thus far in this model and appear to be immune-driven. Taken together, these results show that Tx-induced early EC dysfunction, as described in patients, may be studied in the model of rat aortic Tx.
Transgenic Rabbits Expressing Human Apolipoprotein(a) Develop More Extensive Atherosclerotic Lesions in Response to a Cholesterol-Rich Diet
Authors: Fan Jianglin , Shimoyamada Hiroaki , Sun Huijun , Marcovina Santica , Honda Kazuo , Watanabe Teruo
Published: June 2011

Abstract
—High lipoprotein(a) [Lp(a)] levels constitute an independent risk factor for the development of atherosclerosis. However, the relationship between Lp(a) and atherosclerosis is not fully understood. To examine the effect of Lp(a) on the development of atherosclerosis, we studied transgenic rabbits expressing human apolipoprotein(a) [apo(a)], which was assembled into Lp(a) in the plasma. Human apo(a) transgenic rabbits fed a 0.3% cholesterol diet for 16 weeks had more extensive atherosclerotic lesions than did nontransgenic rabbits, although the cholesterol levels in the plasma of both groups were similarly elevated. Compared with the lesions in control rabbits, the areas of the atherosclerotic lesions in human apo(a) transgenic rabbits were significantly increased in the aorta, the iliac artery, and the carotid artery. Furthermore, human apo(a) transgenic rabbits on a cholesterol-rich diet had a greater degree of coronary atherosclerosis than did control rabbits. Immunohistochemical analysis revealed that human apo(a) was frequently deposited in the atherosclerotic lesions of transgenic rabbits. We conclude that Lp(a) may have proatherogenic effects in the setting of a cholesterol-rich diet in transgenic rabbits.
Thromboregulation by Endothelial Cells
Authors: Marcus Aaron J. , Broekman M. Johan , Drosopoulos Joan H.F. , Pinsky David J. , Islam Naziba , Gayle Richard B. , Maliszewski Charles R.
Published: June 2011

Abstract
—During their 7- to 9-day lifespan in the circulation, platelets perform an ill-defined baseline function that maintains the integrity of the vasculature. In thrombocytopenic states, there is an increase in vascular permeability and fragility, which is presumably due to absence of this platelet function. In sharp contrast, biochemical or physical injury in the coronary, carotid, or peripheral arteries induces platelet activation and platelet recruitment, which can progress to thrombotic vascular occlusion. Because there is 1 death every 33 seconds from vascular occlusion in the United States, this problem has critical public health implications. In this review, we describe the characterization of a novel potential antithrombotic agent with a unique mode of action—biochemical “deletion” of ADP from an activated platelet releasate, which thereby inhibits platelet recruitment and further activation.
Does Therapeutic Intervention Achieve Slowing of Progression or Bona Fide Regression of Atherosclerotic Lesions?
Authors: Stein Y. , Stein O.
Published: June 2011

Abstract
—This review focuses on the regression of atherosclerosis in humans and experimental animals. It highlights the difficulties to determine unequivocally whether with a given therapeutic intervention, such as diet, drugs, or apheresis, the progression of lesions was curtailed or bona fide regression of atherosclerotic lesions was achieved. It seems appropriate to mention that 2 very different ways to measure regression were used in experimental animals and in humans. Regression in animals was determined mainly in the aorta or coronary arteries isolated at post mortem, and the criteria used were degree of sudanophilia and/or aortic wall thickness and cellular composition or cholesterol content. In humans, the evaluation of regression relied mainly on quantitative coronary angiography. The literature of the past decade is reviewed selectively but not exhaustively, and in some instances, a brief historical overview is given.
Superoxide Anions and Endothelial Cell Proliferation in Normoglycemia and Hyperglycemia
Authors: Zanetti Michela , Zwacka Ralph M. , Engelhardt John F. , Katusic Zvonimir S. , O’Brien Timothy
Published: June 2011

Abstract
—Oxygen free radicals are believed to play a key role in cellular proliferation, and increased concentrations of these molecules have been implicated in the pathogenesis of endothelial dysfunction in diabetes mellitus. Our aim was to study the role of superoxide anions in endothelial cell proliferation under conditions of normoglycemia and hyperglycemia. Human aortic endothelial cells (HAECs) and human umbilical vein endothelial cells (HUVECs) exposed to adenoviral vectors encoding CuZnSOD (AdCuZnSOD), β-galactosidase (Adβgal), or diluent (control) were cultured in normal glucose (NG, 5.5 mmol/L) or high glucose (HG, 28 mmol/L) medium. Cell proliferation was compared by use of [
3
H]thymidine incorporation and cell count in transduced and control cells in the setting of NG and HG. Transgene expression was detected in transduced cells by X-gal staining and by Western analysis and SOD activity assay in AdCuZnSOD-transduced cells. Superoxide production was significantly (
P
<0.05) decreased in AdCuZnSOD-transduced cells cultured in both NG and HG medium. In NG, AdCuZnSOD-transduced endothelial cells had decreased proliferation compared with control cells. After 48 hours in HG, superoxide levels were increased and DNA synthesis was decreased (
P
<0.05) in control and Adβgal-transduced but were not affected in AdCuZnSOD-transduced cells. In addition, after 7 days in HG, cell counts were reduced (
P
<0.05) in control (73±2.5%) and Adβgal-transduced (75±3.4%) but not in AdCuZnSOD-transduced cells (89±3.4%). These results suggest that either a deficiency or an excess of superoxide anions inhibits endothelial cell proliferation, and the inhibitory effect of increased superoxide due to hyperglycemia can be reversed by CuZnSOD overexpression.
Low Blood Flow After Angioplasty Augments Mechanisms of Restenosis
Authors: Ward Michael R. , Tsao Philip S. , Agrotis Alex , Dilley Rodney J. , Jennings Garry L. , Bobik Alex
Published: June 2011

Abstract
—The predominant cause of restenosis after angioplasty is now thought to be inward remodeling, but the mechanisms responsible are unknown. Remodeling in normal vessels is regulated by the endothelium in response to altered shear stress. Although the endothelium is often damaged by angioplasty, restenosis rates after angioplasty have been correlated with impaired coronary flow. Thus, we examined how increases or decreases in blood flow through balloon catheter–injured rat carotid arteries affect vessel morphometry (4, 10, and 28 days), cell migration (4 days), and levels of promigratory mRNAs (2 and 10 days). After 28 days, the luminal area in vessels with low blood flow was significantly less than in those with normal and high blood flow (0.17±0.01 [low] versus 0.24±0.06 [normal] versus 0.30±0.02 [high] mm
2
,
P
<0.01), predominantly because of accentuated inward remodeling (or reduced area within the external elastic lamina; 0.42±0.02 [low] versus 0.54±0.07 [normal] versus 0.53±0.04 [high] mm
2
,
P
<0.05). Low flow also enhanced smooth muscle cell migration 4 days after injury by 90% above normal and high flows (
P
<0.01). Two days after injury, low flow significantly increased levels of mRNAs encoding promigratory peptides (integrin α
v
β
3
, transforming growth factor-β
1
, CD44v6, MDC9, urokinase plasminogen activator receptor, and β-inducible gene h3); these changes persisted 10 days after injury and were localized to the neointima. Low blood flow may promote restenosis after angioplasty because of its adverse effect on vessel remodeling, and it is associated with the augmented expression of multiple genes central to cell migration and restenosis.
Tamoxifen and Cardiac Risk Factors in Healthy Women
Authors: Cushman Mary , Costantino Joseph P. , Tracy Russell P. , Song Kyunghee , Buckley Lenore , Roberts John D. , Krag David N.
Published: June 2011

Abstract
—Tamoxifen reduces the incidence of breast cancer in women at risk for that disease. Because heart disease is the leading cause of death in women and because tamoxifen is also associated with venous thrombosis, an improved understanding of the association of tamoxifen with cardiovascular disease risk factors is required. In 111 healthy women at a single center, who were participating in a randomized double-blind breast cancer prevention trial, the 6-month effects of oral tamoxifen (20 mg/d) compared with placebo on factors related to inflammation, hemostasis, and lipids were studied. Tamoxifen was associated with reductions of 26% in median C-reactive protein, 22% in median fibrinogen, and 9% in cholesterol (all
P
<0.01 compared with placebo). There were no differences in treatment effects on factor VII coagulant activity, fragment 1-2, and triglycerides. In secondary analyses, the effect of tamoxifen on C-reactive protein was larger in postmenopausal women and in women with higher waist-to-hip ratios. The effect on fibrinogen was larger in women with higher baseline cholesterol. Tamoxifen demonstrated effects on inflammatory markers that were consistent with reduced cardiovascular risk. These findings are in contrast to recent reports of increased C-reactive protein associated with postmenopausal estrogen. The potential for beneficial cardiovascular effects of tamoxifen in healthy women is suggested.
Elevated Circulating Levels of Monocyte Chemoattractant Protein-1 in Patients With Restenosis After Coronary Angioplasty
Authors: Cipollone Francesco , Marini Matteo , Fazia Maria , Pini Barbara , Iezzi Annalisa , Reale Marcella , Paloscia Leonardo , Materazzo Guido , D’Annunzio Erminio , Conti Pio , Chiarelli Francesco , Cuccurullo Franco , Mezzetti Andrea
Published: June 2011

Abstract
—Inflammation plays a pathogenic role in the development of restenosis after percutaneous transluminal coronary angioplasty (PTCA). Monocyte chemoattractant protein-1 (MCP-1) is a potent chemoattractant of monocytes; however, its role in the pathophysiology of restenosis is still unclear. We set out to investigate the role of MCP-1 in restenosis after PTCA. In addition, we tested the hypothesis that MCP-1 exerts its effect, at least in part, by inducing O
2
−
generation in circulating monocytes. Plasma levels of MCP-1 were measured before and 1, 5, 15, and 180 days after PTCA in 50 patients (30 males and 20 females, aged 62±5 years) who underwent PTCA and who had repeated angiograms at 6-month follow-up. Restenosis occurred in 14 (28%) patients. The MCP-1 level was no different at baseline between patients with or without restenosis. However, after the procedure, restenotic patients, compared with nonrestenotic patients, had statistically significant (
P
<0.0001) elevated levels of MCP-1. In contrast, plasma levels of other chemokines, such as RANTES and interleukin-8, did not differ between the 2 groups after PTCA. Higher MCP-1 throughout the study was correlated with restenosis. Moreover, increased MCP-1 was significantly correlated with increased monocyte activity, as reflected by enhanced O
2
−
generation. Finally, multivariate regression analysis showed that the MCP-1 plasma level measured 15 days after PTCA was the only statistically significant independent predictor of restenosis (β=0.688,
P
<0.0001). This study suggests that MCP-1 production and macrophage accumulation in the balloon-injured vessel may play a pivotal role in restenosis after PTCA. MCP-1 may induce luminal renarrowing, at least in part, by inducing O
2
−
release in monocytes. Further understanding of the mechanism(s) by which MCP-1 is produced and acts after arterial injury may provide insight into therapies to limit the progression of atherosclerosis and restenosis after balloon angioplasty.
Role of Sp1 in the Induction of p27 Gene Expression in Vascular Smooth Muscle Cells In Vitro and After Balloon Angioplasty
Authors: Andrés Vicente , Ureña Jesús , Poch Enric , Chen Donghui , Goukassian David
Published: June 2011

Abstract
—The abnormal proliferation of vascular smooth muscle cells (VSMCs) plays an important role in atherosclerosis and restenosis. Although several studies have implicated the growth inhibitory protein p27
Kip1
(p27) in the control of myocyte growth and hypertrophy, little is known about the molecular mechanisms that regulate p27 expression in the cardiovascular system. In the present study, we demonstrate the interaction of the transcription factor Sp1 with 2 GC-rich sequences within the p27 promoter in cultured VSMCs. Importantly, point mutations that disrupted Sp1 binding markedly reduced p27 promoter activity, demonstrating that Sp1 is required for efficient p27 gene transcription in cultured VSMCs. Because p27 expression is upregulated after balloon angioplasty, we investigated Sp1 expression and activity in control and balloon-injured rat carotid arteries to assess the role of Sp1 as a physiological regulator of p27 expression. Although immunohistochemical analysis disclosed Sp1 protein expression in both control and balloon-injured arteries, a high level of Sp1 DNA-binding activity was found only in response to balloon angioplasty. Collectively, these results demonstrate that Sp1 is essential for maximum p27 promoter activity in VSMCs and suggest that posttranslational induction of Sp1 DNA-binding activity contributes to the induction of p27 expression and VSMC growth arrest at late time points after balloon angioplasty.
Regional Differentiation of Desmin, Connexin43, and Connexin45 Expression Patterns in Rat Aortic Smooth Muscle
Authors: Ko Yu-Shien , Coppen Steven R. , Dupont Emmanuel , Rothery Stephen , Severs Nicholas J.
Published: June 2011

Abstract
—The gap-junctional protein, connexin43, is differentially expressed in vascular smooth muscle cells (SMCs) according to phenotype. Previous studies suggest that desmin-negative SMCs are characterized by high levels of connexin43, whereas desmin-positive SMCs (of a more contractile phenotype) typically have low connexin43 levels. In this study, we examine systematically the inverse relationship between connexin43 and desmin in SMCs of defined regions of the rat aortic media and determine whether additional connexin isotypes are expressed and contribute to this relationship. Immunoconfocal microscopy demonstrated that (1) the inverse relationship between connexin43 and desmin expression holds true for the media of sequential aortic zones, with 1 exception, the ascending aorta, and (2) an additional vascular connexin, connexin45, is expressed by aortic SMCs. Examination of connexin43, connexin45, and desmin expression in sequential aortic zones reveals 3 SMC subpopulations. The first, predominating in the aortic arch and thoracic aorta, is desmin negative and contains high connexin43 levels; the second, predominating in the abdominal aorta and iliac artery, is desmin positive and contains low connexin43 levels; and the third, which is restricted to the ascending aorta, is desmin positive and expresses high connexin43 levels. Connexin45 levels are high in the ascending aorta but low in the other aortic segments. In para-aortic veins, a fourth SMC subpopulation appears, one that is desmin positive and contains connexin45 but not connexin43. These results demonstrate that a diversity of connexin expression patterns characterizes distinctive subpopulations of medial SMCs in situ with a potential to contribute to regional differentiation of vascular function.
Effect of Probucol in Lecithin-Cholesterol Acyltransferase–Deficient Mice
Authors: Tomimoto Shigehiro , Tsujita Maki , Okazaki Mitsuyo , Usui Shinichi , Tada Toyohiro , Fukutomi Tatsuya , Ito Shigenori , Itoh Makoto , Yokoyama Shinji
Published: June 2011

Abstract
—Cellular cholesterol release takes place by at least 2 distinct mechanisms: the lecithin-cholesterol acyltransferase (LCAT)-driven net efflux by cholesterol diffusion and the generation of high density lipoprotein (HDL) with cellular cholesterol and phospholipid on the cell-apolipoprotein interaction. Therefore, LCAT deficiency impairs the former pathway, and the latter can be inhibited by probucol, which interferes with the apolipoprotein-cell interaction. Hence, probucol was given to the LCAT-deficient mice in the attempt to suppress both of these pathways. The mice were fed low (0.2%) and high (1.2%) cholesterol diets containing 0.5% probucol for 2 weeks. LCAT deficiency and probucol markedly decreased plasma HDL, and the effects were synergistic. Tissue cholesterol content was lower in the adrenal glands and ovaries in the LCAT-deficient mice and in the probucol-treated mice, suggesting that HDL is a main cholesterol provider for these organs. It was also moderately decreased in the spleen of the low cholesterol–fed female mice and in the thyroid gland of the low cholesterol–fed male mice. On the other hand, the esterified cholesterol content in the liver was substantially increased by the probucol treatment with a high cholesterol diet in the LCAT-deficient mice but not in the wild-type mice. Among the groups, there was no significant difference in the tissue cholesterol levels in other organs, such as the liver, spleen, thymus, brain, erythrocytes, thyroid gland, testis, and aorta, resulting from either LCAT deficiency or probucol. Thus, the apolipoprotein-mediated mechanism plays a significant role in the export of cellular cholesterol in the liver, indicating that the liver is a major site of the HDL assembly. Otherwise, tissue cholesterol homeostasis can largely be maintained in mice even when the assembly of new HDL is inhibited by probucol in the absence of LCAT. Nonspecific diffusion of cholesterol perhaps adequately maintains the homeostasis in the experimental condition.
Accumulation of Triglyceride-Rich Lipoprotein in Subjects With Abdominal Obesity
Authors: Bard J. M. , Charles M. A. , Juhan-Vague I. , Vague P. , André P. , Safar M. , Fruchart J. C. , Eschwege E.
Published: June 2011

Abstract
—The present study represents a new insight into the Biguanides and the Prevention of the Risk of Obesity (BIGPRO) 1 study population at inclusion. This population, selected basically on the basis of a high waist-to-hip ratio (≥0.95 for men and ≥0.80 for women), is supposed to represent a group of patients with insulin resistance. The present study was undergone to establish whether apolipoprotein C-III (apoC-III) and apolipoprotein E (apoE) associated with apo B (apoC-III LpB and apoE LpB, respectively), considered to be markers of remnant accumulation, play a role in the hypertriglyceridemia associated with insulin resistance and whether they are related to other biological abnormalities frequently observed in this syndrome. In this population, the concentration of the markers of remnant accumulation increases with triglyceride levels. Therefore, correlation studies were realized to assess the relative effect of insulin and the markers of remnant accumulation on triglyceride plasma level. As a first attempt, a simple correlation analysis revealed that insulin is positively related to the markers of remnant accumulation only in hypertriglyceridemic patients (triglycerides ≥1.7 mmol/L). To assess the independent contribution of these markers, insulin, and other parameters related to the plasma triglyceride concentration, a stepwise multiple regression analysis was run. Results revealed that insulin and the markers of remnant accumulation (specifically, apoE LpB) are independent contributors to the plasma triglyceride concentration. Markers of the endothelial damage, plasminogen activator inhibitor-1, tissue plasminogen activator, and von Willebrand factor, which are often increased in the case of insulin resistance, were tested for their correlation with the markers of remnant accumulation. Plasminogen activator inhibitor-1 is positively correlated with these markers only in hypertriglyceridemic male subjects. It is concluded that increased insulin levels found in insulin resistance syndrome are associated with an increased production of triglyceride-rich lipoproteins enriched in apoC-III and apoE. The accumulation of these remnants and/or their abnormal composition in apoC-III and apoE could be an explanation for the development of hypertriglyceridemia in this syndrome.
Current Infection With
Helicobacter pylori
, but Not Seropositivity to
Chlamydia pneumoniae
or Cytomegalovirus, Is Associated With an Atherogenic, Modified Lipid Profile
Authors: Hoffmeister Albrecht , Rothenbacher Dietrich , Bode Guenter , Persson Kenneth , März Winfried , Nauck Matthias A. , Brenner Hermann , Hombach Vinzenz , Koenig Wolfgang
Published: June 2011

Abstract
—Infectious agents may be involved in atherothrombogenesis. The potential pathogenic pathway, however, remains unclear. We investigated the association between various infectious agents and lipoproteins known to have an atherogenic effect. We recruited 470 healthy blood donors and 238 patients with angiographically proven coronary heart disease (CHD), aged 40 to 68 years. Seropositivity to
Chlamydia pneumoniae
(CP), chlamydial lipopolysaccharide, and cytomegalovirus (CMV) was determined; infection with
Helicobacter pylori
(HP) was assessed by using the [
13
C]urea breath test. In all subjects, total cholesterol, high density lipoprotein (HDL) cholesterol, lipoprotein(a), and various apolipoproteins (apos) were determined. In unadjusted analysis, mean HDL cholesterol concentration was significantly decreased in HP-positive healthy subjects (1.36 vs 1.44 mmol/L,
P
=0.006) compared with HP-negative subjects. The HDL cholesterol to total cholesterol ratio was significantly decreased in HP-positive (0.259 vs 0.276,
P
=0.01) and CP-seropositive (0.266 vs 0.280,
P
=0.04) healthy subjects compared with (sero)negatives. Mean apoAI levels were significantly lower in HP-positive healthy subjects (1.46 vs 1.51 g/L,
P
=0.03) and in CMV-positive healthy subjects (1.47 vs 1.52 g/L,
P
=0.01) compared with (sero)negative subjects. After multivariable adjustment by means of linear regression analysis, only the association between HP infection and decreased HDL cholesterol (
P
=0.002), decreased HDL cholesterol to total cholesterol ratio (
P
=0.005), decreased apoAI (
P
=0.02), and increased apoB (
P
=0.02) persisted and remained significant. There was no independent association between other lipoproteins and serological markers of CP or CMV infection. Current infection with HP, but not seropositivity to CP or CMV, was associated with an atherogenic, modified lipid profile. These lipid alterations could explain, at least in part, the reported weak association between chronic HP infection and atherosclerotic diseases.
Alcohol Enhances Oxysterol-Induced Apoptosis in Human Endothelial Cells by a Calcium-Dependent Mechanism
Authors: Spyridopoulos Ioakim , Wischhusen Jörg , Rabenstein Björn , Mayer Petra , Axel Dorothea I. , Fröhlich Kai-Uwe , Karsch Karl R.
Published: June 2011

Abstract
—Controversy exists about the net effect of alcohol on atherogenesis. A protective effect is assumed, especially from the tannins and phenolic compounds in red wine, owing to their inhibition of low density lipoprotein (LDL) oxidation. However, increased atherogenesis occurs in subjects with moderate to heavy drinking habits. The purpose of this study was to investigate the influence of alcohol in combination with oxysterols on the endothelium. Cultured human arterial endothelial cells (HAECs) served as an in vitro model to test the cellular effects of various oxysterols. Oxysterols (7β-hydroxycholesterol, 7-ketocholesterol, and cholesterol-5,6-epoxides), which are assumed to be the most toxic constituents of oxidized LDL, induced apoptosis in HAECs through calcium mobilization followed by activation of caspase-3. Ethanol, methanol, isopropanol,
tert
-butanol, and red wine all potentiated oxysterol-induced cell death up to 5-fold, paralleled by further induction of caspase-3. The alcohol effect occurred in a dose-dependent manner and reached a plateau at 0.05% concentration. Alcohol itself did not affect endothelial cell viability, nor did other solvents such as dimethyl sulfoxide mimic the alcohol effect. So far as the physiologically occurring oxysterols are concerned, this effect was apparent only for oxysterols oxidized at the steran ring. The possibility of alcohol facilitating the uptake of oxysterols into the cell was not supported by the data from an uptake study with radiolabeled compounds. Finally, alcohol in combination with oxysterols did cause a dramatic increase in cytosolic calcium influx. Blockage of calcium influx by the calcium channel blocker aurintricarboxylic acid or the calcium chelator ethylene glycol-bis(β-aminoethyl ether)-
N
,
N
,
N’
,
N’
-tetraacetic acid abrogated the alcohol-mediated enhancement of oxysterol toxicity. We describe for the first time a mechanistic concept explaining possible adverse effects of alcohol in conjunction with physiologically occurring oxysterols on atherogenesis.
Paraoxonase and Atherosclerosis
Authors: Durrington P. N. , Mackness B. , Mackness M. I.
Published: June 2011

Abstract
—There is considerable evidence that the antioxidant activity of high density lipoprotein (HDL) is largely due to the paraoxonase-1 (PON1) located on it. Experiments with transgenic PON1 knockout mice indicate the potential for PON1 to protect against atherogenesis. This protective effect of HDL against low density lipoprotein (LDL) lipid peroxidation is maintained longer than is the protective effect of antioxidant vitamins and could thus be more important. There is evidence that the genetic polymorphisms of PON1 least able to protect LDL against lipid peroxidation are overrepresented in coronary heart disease, particularly in association with diabetes. However, these polymorphisms explain only part of the variation in serum PON1 activity; thus, a more critical test of the hypothesis is likely to be whether low serum PON1 activity is associated with coronary heart disease. Preliminary case-control evidence suggests that this is indeed the case and, thus, that the quest for dietary and pharmacological means of modifying serum PON1 activity may allow the oxidant model of atherosclerosis to be tested in clinical trials.
HDL and the Inflammatory Response Induced by LDL-Derived Oxidized Phospholipids
Authors: Navab Mohamad , Berliner Judith A. , Subbanagounder Ganesamoorthy , Hama Susan , Lusis Aldons J. , Castellani Lawrence W. , Reddy Srinivasa , Shih Diana , Shi Weibin , Watson Andrew D. , Van Lenten Brian J. , Vora Deven , Fogelman Alan M.
Published: June 2011

Abstract
—Oxidation of low density lipoprotein (LDL) phospholipids containing arachidonic acid at the
sn
-2 position occurs when a critical concentration of “seeding molecules” derived from the lipoxygenase pathway is reached in LDL. When this critical concentration is reached, the nonenzymatic oxidation of LDL phospholipids produces a series of biologically active, oxidized phospholipids that mediate the cellular events seen in the developing fatty streak. Normal high density lipoprotein (HDL) contains at least 4 enzymes as well as apolipoproteins that can prevent the formation of the LDL-derived oxidized phospholipids or inactivate them after they are formed. In the sense that normal HDL can prevent the formation of or inactivate these inflammatory LDL-derived oxidized phospholipids, normal HDL is anti-inflammatory. HDL from mice that are genetically predisposed to diet-induced atherosclerosis became proinflammatory when the mice are fed an atherogenic diet, injected with LDL-derived oxidized phospholipids, or infected with influenza A virus. Mice that were genetically engineered to be hyperlipidemic on a chow diet and patients with coronary atherosclerosis, despite normal lipid levels, also had proinflammatory HDL. It is proposed that LDL-derived oxidized phospholipids and HDL may be part of a system of nonspecific innate immunity and that the detection of proinflammatory HDL may be a useful marker of susceptibility to atherosclerosis.
Nitric Oxide Differentially Regulates Induction of Type II Nitric Oxide Synthase in Rat Vascular Smooth Muscle Cells Versus Macrophages
Authors: Zhang Hanfang , Snead Connie , Catravas John D.
Published: June 2011

Abstract
—We studied effects of nitric oxide (NO) released by different NO donors on induction of inducible NO synthase (iNOS) in rat aortic smooth muscle cells (RASMC) and rat macrophage cell line NR8383. iNOS protein expression induced by a CM (interleukin-1β 250 U/mL, interferon-γ 150 U/mL, and tumor necrosis factor-α 150 U/mL) was not affected by the NO donor SNAP (0.2 to 1 mmol/L) in RASMC at 24 hours of incubation but was dose-dependently decreased by SNAP in macrophages (maximal 60% inhibition). A fully functional −3.2-kb rat iNOS promoter was transfected into RASMC and macrophages. The CM-induced promoter activity in transfected macrophages was inhibited by SNAP (maximal 67% inhibition), but this inhibitory effect by SNAP was not observed in transfected RASMC. Electrophoretic mobility-shift assays demonstrated that nuclear factor-κB (NF-κB) binding patterns were different in 2 cell types and that the ratio of p50:p65 subunits was significantly lower in macrophages than in RASMC. Furthermore, NF-κB activity was not affected by SNAP in RASMC but was reduced by SNAP in macrophages. Another putative NO donor, NOR3 (1 mmol/L), completely inhibited iNOS induction by CM in RASMC, but this was accompanied by severe cytotoxicity, which resulted in cell death. Similar concentrations of SNAP did not exhibit cytotoxicity in RASMC, whereas macrophages demonstrated 88% viability compared with cells without SNAP. NO synthase inhibitor
N
g
-monomethyl-
l
-arginine significantly inhibited CM-induced nitrite production in both cell types and stimulated iNOS protein expression in macrophages but did not affect iNOS expression in RASMC. These data strongly suggest that NO may affect transcriptional regulation of iNOS differently in RASMC versus macrophages, possibly by means of regulation of NF-κB activation.
Expression of Angiopoietin-1 in Human Glioblastomas Regulates Tumor-Induced Angiogenesis
Authors: Audero Enrica , Cascone Ilaria , Zanon Ilaria , Previtali Stefano C. , Piva Roberto , Schiffer Davide , Bussolino Federico
Published: June 2011

Abstract
—To define a role for the angiopoietin/Tie2 system in astrocytoma angiogenesis, we examined the expression of angiopoietin-1 (Ang1) and angiopoietin-2 (Ang2) in these tumors by immunohistochemistry and in situ hybridization. Furthermore, we studied in vitro the effects elicited by glioblastoma cell–secreted Ang1 or by recombinant Ang1 on functions of endothelial cells (ECs). Our observations of astrocytomas show that a stage-specific induction of angiopoietins occurs and is correlated with angiogenic phases of different intensity. Ang1 expression was found in a few astrocytes scattered in the tumor at all stages of astrocytoma progression. In blood vessels, Ang1 mRNA increased progressively in high-grade glioblastomas, in which the number of vessels was higher than in low-grade tumors. Ang2 was detected in tumor cells and in ECs in high-grade astrocytomas, whereas its expression was negligible in low-grade tumors. Coculture of glioblastoma cell lines producing Ang1 with endothelium demonstrated a key role of this ligand in the control of EC network organization. We found that recombinant Ang1 in vitro induces EC spreading and reorganization of the cell monolayer into cordlike structures. These results suggest that Ang1 directly acts on ECs by modulating cell-cell and cell-matrix associations and promoting the differentiation phase of angiogenesis.
Decreased Smooth Muscle Cell/Extracellular Matrix Ratio of Media of Femoral Artery in Patients With Atherosclerosis and Hyperhomocysteinemia
Authors: Vermeulen E. G. J. , Niessen H. W. M. , Bogels M. , Stehouwer C. D. A. , Rauwerda J. A. , van Hinsbergh V. W. M.
Published: June 2011

Abstract
—The aim of this study was to determine whether the morphology of the muscular femoral artery in patients with atherosclerosis and hyperhomocysteinemia differs from that of atherosclerotic vessels from patients with normal homocysteine levels. Whole-vessel biopsies of the superficial femoral artery were taken from patients with symptomatic atherosclerotic disease with and without hyperhomocysteinemia and from patients without atherosclerosis from traumatic amputations. The morphology of these specimens was studied qualitatively by light and electron microscopy and quantitatively by light microscopy in combination with a video overlay system. Atherosclerotic lesions in patients with hyperhomocysteinemia were morphologically similar to those in patients with normal homocysteine levels, except for a significantly decreased smooth muscle cell/extracellular matrix ratio of the media in hyperhomocysteinemic patients (
P
=0.02 versus normohomocysteinemic atherosclerotic group and
P
=0.001 versus group without a history of cardiovascular disease). Hyperhomocysteinemia is associated with a significant decrease of the smooth muscle cell/extracellular matrix ratio of the media of muscular femoral arteries without significant changes in medial thickness. Further investigations should concentrate on the cause of this newly discovered phenomenon and its impact on vascular compliance.
Chlamydia pneumoniae
Does Not Increase Atherosclerosis in the Aortic Root of Apolipoprotein E–Deficient Mice
Authors: Aalto-Setälä Katriina , Laitinen Kirsi , Erkkilä Leena , Leinonen Maija , Jauhiainen Matti , Ehnholm Christian , Tamminen Minna , Puolakkainen Mirja , Penttilä Ilkka , Saikku Pekka
Published: June 2011

Abstract
—In epidemiological studies, an association between cardiovascular disease and
Chlamydia pneumoniae
(
C pneumoniae
) infection has been observed. Although
C pneumoniae
has been shown to be present in atherosclerotic lesions, a causal relationship between
C pneumoniae
infection and atherosclerosis has not been demonstrated. To study this question, we used 2 strains of apolipoprotein (apo) E–deficient mice. Eight-week-old mice on an FVB background that were maintained on either a low- or a high-fat diet were infected 3 times at 1-week intervals with
C pneumoniae
, and atherosclerotic lesions were measured in the aortic root at 10 weeks after the primary infection. In each of the diet groups, no difference in the extent of atherosclerosis could be observed between the
C pneumoniae
–infected and control animals. In further studies, 2 strains of apoE-deficient mice (FVB or C57BL/6J background) were infected 4 times at 3- to 4-week intervals, and the extent of atherosclerosis was analyzed 18 weeks later. The mice were kept on either a low- or a high-fat diet. The high-fat diet increased atherosclerosis, and a difference in atherosclerosis susceptibility between the mouse strains was observed. However,
C pneumoniae
infection did not influence lesion size in either mouse strain. On the other hand,
C pneumoniae
could not be demonstrated by polymerase chain reaction in any of the atherosclerotic lesions of the infected animals studied. A small decrease in serum cholesterol and triglyceride levels 3 days after the primary infection occurred, but after that no differences in serum lipid levels compared with those in noninfected animals were evident. In the myocardium of
C pneumoniae
–infected mice, no inflammatory signs could be observed. We conclude that under the experimental conditions used,
C pneumoniae
infection does not accelerate atherogenic changes in the aortic root of apoE-deficient mice.