bluuebunny/crossref_metadata_2025 huggingface dataset:
Migration of leukocytes through the vessel wall and beyond
Authors: Yadav Rashmi , Larbi Karen , Young Rebecca , Nourshargh Sussan
Published: September 2003

The migration of leukocytes from the vascular lumen to sites of infection and/or injury in the extravascular tissue involves a series of sequential and coordinated molecular and cellular events with the resultant primary response being that of reduced leukocyte velocity within the blood stream, followed by leukocyte firm adhesion to endothelial cells lining the vessel wall and eventually migration through the vessel wall. Despite the growing knowledge of the mechanisms that mediate initial interaction of leukocytes with the endothelium, very little is known about the mechanisms that mediate and regulate leukocyte migration through the venular wall, the endothelium and its associated perivascular basement membrane. This review, whilst giving a brief outline of the stepwise cascade of molecular interactions involved in this process and the methods employed to investigate leukocyte migration in vivo, focuses primarily on mechanisms of leukocyte transmigration, the final step in the process of leukocyte emigration. Furthermore, special emphasis is placed on discussing the process and the mechanisms involved in leukocyte migration through the basement membrane, a structure that presents significant impedance to transmigrating leukocytes but is seldom investigated in the context of leukocyte transmigration in vivo. The review also discusses the growing evidence supporting the concept that leukocyte transmigration is not only a response that describes the passage of leukocytes through the venular wall, but also acts as a means of regulating leukocyte responsiveness beyond the vessel wall, i.e. within the extravascular tissue.

This publication was partially financed by Serono Foundation for the Advancement of Medical Science.

Part of this paper was originally presented at the 2nd International Workshop on New Therapeutic Targets in Vascular Biology from February 6-9, 2003 in Geneva, Switzerland.
High molecular weight kininogen and factor XII binding to endothelial cells and astrocytes
Authors: Fernando Lawrence , Natesan Snehlatha , Joseph Kusumam , Kaplan Allen
Published: September 2003

We have quantitated the binding of high molecular weight kininogen (HK) to human microvascular endothelial cells of lung and dermal origin as well as to astrocytes and compared the results with those reported for human umbilical vein endothelial cells (HUVEC). We also reassessed parameters of binding to HUVEC employing cells in suspension as well as cells attached to the culture plate and report similar numbers of sites varying from 6.96x105to 7.71x105per cell. The present study shows that HK binds with high specificity and affinity to microvascular endothelial cells (Kd = 1.86 to 4.5 nM) compared to HUVEC (Kd = 10.35nM) but with lower affinity to astrocytes (Kd = 23.73 nM). Human cytokeratin 1, urokinase plasminogen activator receptor and gC1qR were found to be HK binding proteins present at the surface of microvascular endothelial cells and astrocytes analogous to that seen in HUVEC, as assessed by inhibition of binding with antibody to each protein. Lung microvascular endothelial cells had approximately half the number of HK binding sites as HUVEC while dermal micro vascular endothelial cells and astrocytes had only 8-10% of the sites/cell. The affinity of binding to the microvascular endothelial cells was greater than HUVEC, the affinity of binding to astrocytes was considerably less, nevertheless binding to each cell type involves gC1qR, cytokeratin 1 and u-PAR to varying degrees. We also demonstrate, for the first time, that factor XII binds to all of these cell types in a saturable and Zn+2dependent manner. Given that factor XII accelerates the interactions among cell surfaces and proteins of the contact activation cascade to generate bradykinin, binding of factor XII (and the prekallikrein-HK complex) may serve as a mechanism by which these proteins are concentrated locally to facilitate their interactions.
Statins as novel immunomodulators: From cell to potential clinical benefit
Authors: Mach François
Published: September 2003

In the last decades, substantial progress has been made in understanding the relationship between lipid disorders and prevention of cardiac ischemic disease. Statins competitively inhibit 3-hydroxyl-3-methylglutaryl coenzyme A (HMG-CoA) reductase, an enzyme crucial to cholesterol biosynthesis. Statins have long been thought to exert their benefits by reducing cholesterol synthesis, but the fact that mevalonate is the precursor of isoprenoids that regulate diverse cellular functions has led investigators to examine pleiotropic effects for these agents. Statins have never been shown to be involved in the immune response, although two clinical trials have suggested that in heart transplant patients, statin therapy has beneficial effects on the incidence of cardiac rejection, coronary vasculopathy, and survival.

Major Histocompatibility Complex class II (MHC-II) molecules, which affect the immune response and organ rejection after transplantation, may be induced by the pro-inflammatory cyto-kine interferon gamma (IFN-γ). Recently, it has been demonstrated that statins repress the induction of MHC-II by IFN-γ in vitro, and thus may suggest a potential role for statins as immunosuppressive agents in vivo. Indeed, two recent in vivo studies performed on different animal models provide further evidence that statin-treatment positively influence immunological disorders.

This publication was partially financed by Serono Foundation for the Advancement of Medical Science.

Part of this paper was originally presented at the 2nd International Workshop on New Therapeutic Targets in Vascular Biology from February 6-9, 2003 in Geneva, Switzerland.
Platelet-leukocyte aggregation under shear stress: Differential involvement of selectins and integrins
Authors: Hu Hu , Varon David , Hjemdahl Paul , Savion Naphtali , Schulman Sam , Li Nailin
Published: September 2003

Platelets and leukocytes can form heterotypic aggregates. We studied how shear stress influences platelet-leukocyte aggregation (PLA). Shear stress was applied to hirudinized blood, using a cone-and-plate(let) analyzer. Platelet and leukocyte activation and PLA formation were monitored by flow cytometry. Shear stress per se increased platelet P-selectin expression, leukocyte CD11b expression, and PLA formation. Shear-induced hetero-typic aggregation was seen among monocytes and neutrophils, but not lymphocytes. ADP induced marked PLA formation, but this was reduced by shear stress. fMLP mildly increased PLA formation, and this effect was enhanced by shear stress. P-selec-tin blockade abolished, whilst GPIIb/IIIa blockade enhanced shear- and agonist-induced PLA formation. At 1800 s-1, shear-and agonist-induced PLA formation were maintained or further enhanced with GPIIb/IIIa blockade alone, but reduced by simultaneous blockade of GPIIb/IIIa, CD11b, and CD18. In conclusion, shear stress per se enhances PLA formation. With agonist stimulation, shear stress enhances PLA formation primarily mediated by integrins, but attenuates PLA formation primarily mediated by P-selectin. The present results indicate that P-selectin-mediated bridging is essential for the initiation of PLA formation, while integrin-bridgings contribute importantly to the stability of heterotypic conjugates under high shear stress.
Restricted BV gene usage by factor VIII-reactive CD4+ T cells in inhibitor-positive patients with severe hemophilia A
Authors: Bayry Jagadeesh , Pashov Anastas , Kaveri Srini , d’Oiron Roseline , Stieltjes Natalie , Roussel-Robert Valeri , Kazatchkine Michel , Boyer Olivier , Lacroix-Desmazes Sébastien , Misra Namita
Published: September 2003

In the present study, we have analyzed the T cell receptor (TCR) repertoires of CD4+ T cells isolated from peripheral blood of 10 inhibitor-positive patients with severe hemophilia A. The distribution of complementarity determining region (CDR3) lengths of the beta chain of the TCRs was analyzed by spectratyping prior to and following in vitrostimulation of the cells with human factor VIII (FVIII). The repertoires of CD4+ T cells of patients were perturbed when compared to those of healthy blood donors. The perturbations of T cell repertoires were heterogeneous among patients with respect to the number and the nature of V-beta (BV) families that exhibited expansion following incubation with FVIII. Some patients showed alterations in one or two BV families, others exhibited more perturbed repertoires affecting 5 to 8 of the 14 BV families tested. Alterations of BV2, BV5 and/or BV9 were consistently found after incubation of CD4+ T cells in the presence of FVIII in 80% of the patients. These findings indicate that the presence of FVIII inhibitors in patients with severe hemophilia A is associated with measurable perturbations of the CD4+ T cell repertoire that results from oligoclonal expansion of FVIII-specific cells and may be relevant for the design of strategies aimed at modulating the anti-FVIII immune responses by T cell-targeted therapy
Elevated Carotid Artery Intima-Media Thickness Levels in Individuals Who Subsequently Develop Type 2 Diabetes
Authors: Hunt Kelly J. , Williams Ken , Rivera David , O’Leary Daniel H. , Haffner Steve M. , Stern Michael P. , González Villalpando Clicerio
Published: September 2003

Objective—

We examined whether B-mode ultrasound–detected carotid artery intima-media thickness (IMT) was elevated before the onset of clinical diabetes.

Methods and Results—

The study population for these analyses included 1127 nondiabetic participants, 66 prediabetic participants, and 303 diabetic participants with a mean age of 49.8 years who participated in the Mexico City Diabetes Study, a prospective cohort study. Common carotid artery (CCA) and internal carotid artery (ICA) IMTs were measured bilaterally by B-mode ultrasound. Age- and sex-adjusted mean ICA and CCA IMTs were both significantly higher among prediabetic individuals {0.81 mm [95% confidence interval (CI), 0.75–0.88] and 0.72 mm [95% CI, 0.69–0.75], respectively} than in individuals who remained free of diabetes [0.71 mm (95% CI, 0.69–0.72) and 0.69 mm (95% CI, 0.68–0.69), respectively]. However, after adjustment for established cardiovascular risk factors, ICA IMT, but not CCA IMT, remained significantly higher among prediabetic individuals [0.81 mm (95% CI, 0.75–0.88) and 0.71 mm (95% CI, 0.68–0.74)] than in individuals who remained free of diabetes [0.71 mm (95% CI, 0.69–0.72) and 0.69 mm (95% CI, 0.68–0.70)].

Conclusions—

The present study provides direct evidence at the vascular level that atherosclerosis levels are elevated before the clinical onset of diabetes.
Hypoxia and Stretch Regulate Intercellular Communication in Vascular Smooth Muscle Cells Through Reactive Oxygen Species Formation
Authors: Cowan Douglas B. , Jones Mara , Garcia Lina M. , Noria Sabrena , del Nido Pedro J. , McGowan Francis X.
Published: September 2003

Objective—

We hypothesized that the alterations in vasomotor tone and adaptive remodeling responses that occur in the circulation because of hypoxia were dependent on changes in cell to cell communication through regulation of gap junction protein expression and function. Consequently, we studied the amount, distribution, and permeability of the principal vascular smooth muscle cell (VSMC) gap junction protein, connexin43, in rat aortic cultures exposed to oxygen partial pressures of 150 or 15 mm Hg.

Methods and Results—

Immunohistochemical staining, immunoblot assays, and Northern blot analyses demonstrated that connexin43 expression was reversibly increased in hypoxic cultures. As a result, hypoxic cells exhibited greater intercellular communication as determined by fluorescence recovery after photobleaching experiments. Using a fluorogenic substrate, hypoxic VSMCs showed increased reactive oxygen species generation, which could be prevented by the glutathione peroxidase mimic ebselen and the mitochondrial complex I inhibitor rotenone but not with the redox-sensitive thiol pyrrolidine dithiocarbamate. The rise in connexin43 expression attributable to hypoxia could be attenuated by ebselen and rotenone treatment. Interestingly, the previously reported induction of connexin43 expression by tensile stretch was also contingent on oxidative activity.

Conclusions—

Hypoxia and stretch increased gap junctional intercellular communication in VSMCs attributable to enhanced connexin43 expression initiated by reactive oxygen species formation.
Mineral Exploration: Search for the Mechanism of Vascular Calcification and Beyond
Authors: Demer Linda L. , Tintut Yin
Published: September 2003

Research in the area of vascular calcification has grown rapidly in the past decade, and there is a greater understanding of its active regulatory mechanisms. This brief review covers the ideas presented in the 2003 Jeffrey M. Hoeg Award lecture, including the concepts that bone tissue forms in the artery wall in patients with atherosclerosis, that vascular cells undergo osteoblastic differentiation, that bone morphogenetic protein and matrix GLA protein regulate vascular calcification in opposition, that inflammatory cytokines and lipids promote vascular cell calcification but inhibit osteoblastic cell differentiation, that these same factors promote differentiation of bone-resorbing osteoclasts, and that the artery wall may contain osteoclast-like cells with the potential to resorb calcium mineral. The review closes with a mention of therapeutic possibilities and an evolutionary paradigm to explain the reciprocal responses of vascular and bone mineralization to inflammation.
Sustained Decrease in Superoxide Dismutase Activity Underlies Constrictive Remodeling After Balloon Injury in Rabbits
Authors: Leite Paulo F. , Danilovic Alexandre , Moriel Patricia , Dantas Katia , Marklund Stefan , Dantas Ana Paula V. , Laurindo Francisco R.M.
Published: September 2003

Objective—

The redox pathophysiology of vascular repair is incompletely understood. We assessed the role of vascular superoxide dismutase (SOD) activity in oxidative/nitrative stress and caliber loss postinjury (PI).

Methods and Results—

Rabbits submitted to iliac artery balloon overdistension were followed for 14 days PI. Significant decrease in vascular SOD activity occurred at 7 and 14 days PI (by 45% and 34%, respectively, versus control, 96±1 U/mg,
P
<0.05). Separation in concanavalin-A column showed that both extracellular SOD (ecSOD) and CuZn SOD activities were reduced, whereas Western analysis showed normal or augmented protein expression. Immunoreactivity to nitrotyrosine, neuronal NO synthase (NOS), and inducible NOS (iNOS) increased in media and neointima PI; iNOS mRNA also augmented. Administration of ecSOD from days 7 to 14 PI corrected the SOD activity decrease and minimized caliber loss by 59% (
P
=0.007) despite unaltered neointima. Nitrate levels markedly increased with ecSOD in injured artery homogenates (26±5 versus 4±0.3 μmol/L per mg,
P
=0.001). Such increase was 70% inhibited by specific iNOS antagonist 1400w. Nitrotyrosine and neuronal NOS expression decreased after ecSOD.

Conclusions—

Sustained low vascular SOD activity has a key role in constrictive remodeling after injury, promoting oxidative/nitrative stress and impairment of iNOS-derived NO bioavailability. SOD function may critically determine whether iNOS induction is beneficial or deleterious in vivo. (Arterioscler Thromb Vasc Biol. 2003;23:2197-2202.)
Essential Role of Junctional Adhesion Molecule-1 in Basic Fibroblast Growth Factor–Induced Endothelial Cell Migration
Authors: Naik Meghna U. , Vuppalanchi Deepika , Naik Ulhas P.
Published: September 2003

Objective—Recently, we have shown that blocking of junctional adhesion molecule-1/A (JAM-1/A) inhibits basic fibroblast growth factor (bFGF)-induced angiogenesis. Because the process of endothelial cell proliferation is a key initial step of neovascularization, we studied the effect of functional knockdown of JAM-1 on human umbilical vein endothelial cell (HUVEC) adhesion and migration induced by bFGF.

Methods and Results—We introduced small interfering RNAs specific to JAM-1 in HUVECs, stimulated them with bFGF, and studied the resultant adhesion and migration of these cells on vitronectin and fibronectin. We show that depletion of JAM-1 inhibits bFGF-induced HUVEC migration specifically on vitronectin. This inhibition is not attributable to the failure of junctional organization, because expression and distribution of other junctional proteins remained unaffected. This inhibition was in fact attributed to an inability of JAM-1–depleted HUVECs to adhere and spread on vitronectin. Furthermore, we find that JAM-1–depleted HUVECs failed to activate extracellular signal–related kinase (ERK) in response to bFGF treatment.

Conclusions—Our results show that JAM-1 is required for the bFGF-induced ERK activation that leads to endothelial cell migration on vitronectin. These data thus implicate JAM-1 as an integral part of both bFGF and ERK signaling pathways in endothelial cells.
Cyclosporin A Enhances Interleukin-8 Expression by Inducing Activator Protein-1 in Human Aortic Smooth Muscle Cells
Authors: Murakami Ryuichiro , Kambe Fukushi , Mitsuyama Hirohito , Okumura Kenji , Murohara Toyoaki , Niwata Satoru , Yamamoto Ryohei , Seo Hisao
Published: September 2003

Objective—Cyclosporin A (CsA) and tacrolimus (FK506) are widely used as immunosuppressants. However, their use has been hampered by various adverse effects, such as acceleration of atherosclerosis. Interleukin (IL)-8, a chemotactic cytokine, plays an important role in pathogenesis of atherosclerosis. We thus investigated whether synthesis of IL-8 from primary human aortic smooth muscle cells is influenced by CsA and FK506.

Methods and Results—Northern blot analysis revealed that CsA increased IL-8 mRNA level and enhanced its increase by epidermal growth factor or tumor necrosis factor-α. In contrast, FK506 had no effect on the mRNA level. IL-8 accumulation in culture media was also increased by CsA. Stability of IL-8 mRNA was not affected by CsA, whereas luciferase reporter gene assay using the human IL-8 promoter revealed that CsA significantly augmented the promoter activity. Electrophoretic mobility shift assay showed that binding activity of activator protein (AP)-1 was increased by CsA, and introduction of a mutation into the AP-1 site in the promoter abolished its CsA-dependent activation. The increased AP-1 binding activity was accompanied by c-Fos synthesis.

Conclusions—CsA stimulates synthesis of IL-8 via activation of AP-1 in human aortic smooth muscle cells, providing a novel aspect of biological effects of CsA on the cells.
Role of Angiotensin II in Altered Expression of Molecules Responsible for Coronary Matrix Remodeling in Insulin-Resistant Diabetic Rats
Authors: Jesmin Subrina , Sakuma Ichiro , Hattori Yuichi , Kitabatake Akira
Published: September 2003

Objective—

Coronary remodeling based on collagen abnormalities in diabetes might be associated with potential interactions between the matrix metalloproteinase (MMP) system, which regulates extracellular matrix turnover, and the fibrinolytic system, which is involved in the fibrin degradation process. We characterized the profiles of the MMP and fibrinolytic systems in insulin-resistant diabetic rat hearts.

Methods and Results—

By immunohistochemistry and in situ hybridization, transforming growth factor-β
1
(TGF-β
1
) expression increased in coronary vessels, the perivascular area, and cardiomyocytes in diabetic rat hearts. Increased expression of plasminogen activator inhibitor-1 (PAI-1) in coronary vessels and the perivascular area was evident in diabetic hearts. In contrast, diabetic hearts exhibited reduced activity and expression of MMP-2 and decreased expression of membrane type-1 MMP (MT1-MMP). Both intravascular and extravascular collagen type I and III immunoreactivity and fibrin deposition were seen in diabetic coronary vessels. These alterations were reversed to nondiabetic levels by the angiotensin II type 1 receptor blocker candesartan, which prevented the development of perivascular fibrosis observed after Masson’s trichrome staining.

Conclusions—

In addition to upregulation of PAI-1, downregulation of MMP-2 and MT1-MMP might play a crucial role in coronary matrix remodeling in insulin-resistant diabetes. These molecules appear to be regulated by angiotensin II via stimulation of TGF-β
1
.
Pioglitazone Inhibits LOX-1 Expression in Human Coronary Artery Endothelial Cells by Reducing Intracellular Superoxide Radical Generation
Authors: Mehta Jawahar L. , Hu Bo , Chen Jiawei , Li Dayuan
Published: September 2003

Objective—LOX-1, a novel lectin-like receptor for oxidized LDL (ox-LDL), is expressed in response to ox-LDL, angiotensin II (Ang II), tumor necrosis factor (TNF)-α, and other stress stimuli. It is highly expressed in atherosclerotic tissues. Peroxisome proliferator–activated receptor (PPAR)-γ ligands, such as pioglitazone, exert antiatherosclerotic effects. This study examined the regulation of LOX-1 expression in human coronary artery endothelial cells (HCAECs) by pioglitazone.

Methods and Results—Fourth generation HCAECs were treated with ox-LDL, Ang II, or TNF-α with or without pioglitazone pretreatment. All 3 stimuli upregulated LOX-1 expression (mRNA and protein). Pioglitazone, in a concentration-dependent manner, reduced LOX-1 expression (P<0.01 versus ox-LDL, Ang II, or TNF-α alone). Ox-LDL, Ang II, and TNF-α each enhanced intracellular superoxide radical generation, and pioglitazone pretreatment reduced superoxide generation (P<0.01 versus ox-LDL, Ang II, or TNF-α). Furthermore, all 3 stimuli upregulated the expression of the transcription factors nuclear factor-κB and activator protein-1 (determined by electrophoretic mobility shift assay), and pioglitazone pretreatment reduced this expression (P<0.01 versus ox-LDL, Ang II, or TNF-α). To determine the biological significance of pioglitazone-mediated downregulation of LOX-1, we studied monocyte adhesion to ox-LDL–treated HCAECs. Pioglitazone reduced the adhesion of monocytes to activated HCAECs in a fashion similar to that produced by antisense to LOX-1 mRNA.

Conclusions—These observations suggest that the PPAR-γ ligand pioglitazone reduces intracellular superoxide radical generation and subsequently reduces the expression of transcription factors, expression of the LOX-1 gene, and monocyte adhesion to activated endothelium. The salutary effect of PPAR-γ ligands in atherogenesis may involve the inhibition of LOX-1 and the adhesion of monocytes to endothelium.
Transcatheter Angioplasty for Acquired Pulmonary Vein Stenosis After Radiofrequency Ablation
Authors: Qureshi Athar M. , Prieto Lourdes R. , Latson Larry A. , Lane Geoffrey K. , Mesia C. Igor , Radvansky Penelope , White Richard D. , Marrouche Nassir F. , Saad Eduardo B. , Bash Dianna L. , Natale Andrea , Rhodes John F.
Published: September 2003

Background—

Pulmonary vein stenosis has recently been recognized as a complication of radiofrequency ablation for atrial fibrillation. This study evaluates the presentation of affected patients and the role of transcatheter therapy for this patient population.

Methods and Results—

This study used a retrospective review of data from 19 patients (age, 51±13 years) with pulmonary vein stenosis who underwent catheterization and angiography between December 2000 and December 2002. Quantitative perfusion and spiral CT scans were performed for initial diagnosis and follow-up. The median duration between radiofrequency ablation and the reported onset of respiratory symptoms for 18 of 19 patients was 7.5 weeks (0.1 to 48). After the onset of symptoms, all but two patients were initially misdiagnosed with a symptoms-to-diagnosis duration of 16 weeks (2–59). At initial catheterization, 17 of 19 patients had angioplasty in 30 veins with stent placement in 5 vessels when a flap occurred. Overall vessel diameter increased from 2.6±1.6 to 6.6±2.4 mm (
P
<0.0001). There were 4 procedure-related adverse events but no long-term sequelae. Immediate follow-up showed improved flow to involved lung segments. At a median follow-up of 43 weeks (2–92), although repeat angioplasty for restenosis was necessary in 8 of 17 patients, 15 of 17 patients currently have no or minimal persistent symptoms.

Conclusions—

Pulmonary vein stenosis after radiofrequency ablation for atrial fibrillation is often misdiagnosed. Although further follow-up is necessary to determine long-term success, our data indicate better pulmonary vein flow and symptomatic improvement in the majority of patients undergoing dilation of postablation pulmonary vein stenosis.
Percutaneous Pericardial Instrumentation for Endo-Epicardial Mapping of Previously Failed Ablations
Authors: Schweikert Robert A. , Saliba Walid I. , Tomassoni Gery , Marrouche Nassir F. , Cole Christopher R. , Dresing Thomas J. , Tchou Patrick J. , Bash Dianna , Beheiry Salwa , Lam Cathy , Kanagaratnam Logan , Natale Andrea
Published: September 2003

Background—

The epicardial location of an arrhythmia could be responsible for unsuccessful endocardial catheter ablation.

Methods and Results—

In 48 patients referred after prior unsuccessful endocardial ablation, we considered percutaneous, subxiphoid instrumentation of the pericardial space for mapping and ablation. Thirty patients had ventricular tachycardia (VT), 6 patients had a right- and 4 had a left-sided accessory pathway (AP), 4 patients had inappropriate sinus tachycardia, and 4 patients had atrial arrhythmias. Of the 30 VTs, 24 (6 with ischemic cardiomyopathy, 3 with idiopathic cardiomyopathy, and 15 with normal hearts) appeared to originate from the epicardium. Seventeen (71%) of these 24 VTs were successfully ablated with epicardial lesions. The other 7 VTs had early epicardial sites that were inaccessible, predominantly because of interference from the left atrial appendage. Six of these were successfully ablated from the left coronary cusp. In 5 of the 10 patients with an AP, the earliest activation was recorded epicardially. Three of these were right atrial appendage–to–right ventricle APs, and epicardial ablation was successful. No significant complications were observed.

Conclusions—

Failure of endocardial ablation could reflect the presence of an epicardial arrhythmia substrate. Epicardial instrumentation and ablation appeared feasible and safe and provided an alternative strategy for the treatment of patients with a variety of arrhythmias. This was particularly true for VT, including patients without structural heart disease.
Simvastatin Rescues Rats From Fatal Pulmonary Hypertension by Inducing Apoptosis of Neointimal Smooth Muscle Cells
Authors: Nishimura Toshihiko , Vaszar Laszlo T. , Faul John L. , Zhao Guohua , Berry Gerald J. , Shi Lingfang , Qiu Daoming , Benson Gail , Pearl Ronald G. , Kao Peter N.
Published: September 2003

Background—

Pulmonary vascular injury by toxins can induce neointimal formation, pulmonary arterial hypertension (PAH), right ventricular failure, and death. We showed previously that simvastatin attenuates smooth muscle neointimal proliferation and pulmonary hypertension in pneumonectomized rats injected with the alkaloid toxin monocrotaline. The present study was undertaken to investigate the efficacy of simvastatin and its mechanism of reversing established neointimal vascular occlusion and pulmonary hypertension.

Methods and Results—

Pneumonectomized rats injected with monocrotaline at 4 weeks demonstrated severe PAH at 11 weeks (mean pulmonary artery pressure [mPAP]=42 versus 17 mm Hg in normal rats) and death by 15 weeks. When rats with severe PAH received simvastatin (2 mg · kg
−1
· d
−1
by gavage) from week 11, there was 100% survival and reversal of PAH after 2 weeks (mPAP=36 mm Hg) and 6 weeks (mPAP=24 mm Hg) of therapy. Simvastatin treatment reduced right ventricular hypertrophy and reduced proliferation and increased apoptosis of pathological smooth muscle cells in the neointima and medial walls of pulmonary arteries. Longitudinal transcriptional profiling revealed that simvastatin downregulated the inflammatory genes fos, jun, and tumor necrosis factor-α and upregulated the cell cycle inhibitor p27Kip1, endothelial nitric oxide synthase, and bone morphogenetic protein receptor type 1a.

Conclusions—

Simvastatin reverses pulmonary arterial neointimal formation and PAH after toxic injury.
Emergence of Smooth Muscle Cell Endothelin B–Mediated Vasoconstriction in Lambs With Experimental Congenital Heart Disease and Increased Pulmonary Blood Flow
Authors: Black Stephen M. , Mata-Greenwood Eugenia , Dettman Robert W. , Ovadia Boaz , Fitzgerald Robert K. , Reinhartz Olaf , Thelitz Stefan , Steinhorn Robin H. , Gerrets Rene , Hendricks-Munoz Karen , Ross Gregory A. , Bekker Janine M. , Johengen Michael J. , Fineman Jeffrey R.
Published: September 2003

Background—

Endothelin-1 (ET-1) has been implicated in the pathophysiology of pulmonary hypertension. In 1-month-old lambs with increased pulmonary blood flow, we have demonstrated early alterations in the ET-1 cascade. The objective of this study was to investigate the role of potential later alterations of the ET cascade in the pathophysiology of pulmonary hypertension secondary to increased pulmonary blood flow.

Methods and Results—

Eighteen fetal lambs underwent in utero placement of an aortopulmonary vascular graft (shunt) and were studied 8 weeks after spontaneous delivery. Compared with age-matched control lambs, lung tissue ET-1 levels were increased in shunt lambs (317.2±113.8 versus 209.8±61.8 pg/g,
P
<0.05). In shunt lambs (n=9), exogenous ET-1 induced potent pulmonary vasoconstriction, which was blocked by the ET
A
receptor antagonist PD 156707 (n=3). This pulmonary vasoconstriction was mimicked by exogenous Ala
1,3,11,15
ET-1 (4 Ala ET-1), the ET
B
receptor agonist, and was blocked by the ET
B
receptor antagonist BQ 788 (n=3). However, in control lambs (n=7), ET-1 and 4 Ala ET-1 did not change pulmonary vascular tone. In contrast to 4-week-old shunt lambs, immunohistochemistry revealed the emergence of ET
B
receptors on smooth muscle cells in the vasculature of 8-week-old shunt lambs.

Conclusions—

Over time, increased pulmonary blood flow and/or pressure results in the emergence of ET
B
-mediated vasoconstriction, which coincides with the emergence of ET
B
receptors on smooth muscle cells. These data suggest an important role for ET
B
receptors in the pathophysiology of pulmonary hypertension in this animal model of increased pulmonary blood flow.
Autologous Culture-Modified Mononuclear Cells Confer Vascular Protection After Arterial Injury
Authors: Gulati Rajiv , Jevremovic Dragan , Peterson Timothy E. , Witt Tyra A. , Kleppe Laurel S. , Mueske Cheryl S. , Lerman Amir , Vile Richard G. , Simari Robert D.
Published: September 2003

Background—

Bone marrow–derived cells have been shown to contribute to endothelial replacement after vascular injury. In vitro culture of peripheral blood mononuclear cells produces cells with phenotypic characteristics of endothelium. To test the hypothesis that delivery of autologous culture-modified mononuclear cells (CMMCs) to injured arteries could attenuate the vascular response to injury, a rabbit model was studied.

Methods and Results—

Rabbit peripheral blood mononuclear cells were cultured in endothelial growth media for 7 to 12 days, yielding highly proliferative cells with distinct endothelial phenotype (expressing CD31 and endothelial nitric oxide synthase and capable of acetylated LDL uptake). A rabbit model of balloon carotid injury was used to evaluate the effect of day 7 CMMC delivery on vascular responses. Animals underwent balloon injury and immediate delivery of autologous CMMCs or buffered saline by 20 minutes of local dwelling. Fluorescence-labeled CMMCs were detected in all vessel layers 4 weeks after delivery. Colonies of cells that localized to the lumen and stained for endothelial markers were also identified. Local CMMC administration at the time of balloon injury accelerated reendothelialization at 4 weeks compared with saline (
P
<0.05). Moreover, CMMC delivery markedly improved endothelium-dependent vasoreactivity at 4 weeks compared with saline (
P
<0.005). Finally, CMMC treatment reduced neointimal formation by 55% at 4 weeks (
P
<0.05).

Conclusions—

These data demonstrate that delivery of CMMCs to balloon-injured arteries is associated with accelerated reendothelialization, enhanced endothelium-dependent vasoreactivity, and reduced neointimal formation. Thus, delivery of autologous CMMCs represents a novel vasculoprotective approach to attenuate the response to acute vascular injury.
Thrombospondin-4 and Its Variants
Authors: Stenina Olga I. , Desai Shailesh Y. , Krukovets Irene , Kight Kelly , Janigro Damir , Topol Eric J. , Plow Edward F.
Published: September 2003

Background—

In a recent large-scale genetic association study, a single nucleotide polymorphism in the thrombospondin-4 (TSP-4) gene, resulting in a proline-for-alanine substitution at position 387, was associated with a significantly increased risk for premature atherosclerosis. TSP-4 had not previously been implicated in vascular pathology, and very little information is available on its expression and functions.

Methods and Results—

The goal of this study was to assess TSP-4 expression in vessel wall and to identify differences in functions of TSP-4 variants that could account for the proatherogenic effects of the (P387)TSP-4 variant. TSP-4 expression was demonstrated in human endothelial cells (ECs) and vascular smooth muscle cells from brain blood vessels and coronary arteries. (P387)TSP-4 and its fragment (residues 326 to 722), but not the A(387) forms, suppressed EC adhesion and proliferation. The (P387)TSP-4 was more active in inducing the phosphorylation of focal adhesion kinase, consistent with inhibition of proliferation. Both variant fragments increased the proliferation of human aortic smooth muscle cells.

Conclusions—

TSP-4 is expressed by vascular cells and influences the vessel wall by modulating the proliferation of ECs and smooth muscle cells. The A387P substitution is a “gain-of-function” mutation, favoring a form of TSP-4 that interferes with EC adhesion and proliferation and may thereby be proatherogenic.
Evidence for Dysregulation of Dimethylarginine Dimethylaminohydrolase I in Chronic Hypoxia–Induced Pulmonary Hypertension
Authors: Millatt Lesley J. , Whitley Guy StJ. , Li Dechun , Leiper James M. , Siragy Helmy M. , Carey Robert M. , Johns Roger A.
Published: September 2003

Background—

Chronic hypoxia–induced pulmonary hypertension is associated with increased pulmonary expression of nitric oxide synthase (NOS) enzymes. Nevertheless, some reports have indicated decreased pulmonary production of NO in the disease. To address this paradox, we determined pulmonary concentrations of the endogenous NOS inhibitor asymmetric dimethylarginine (ADMA) in the hypoxia-induced pulmonary hypertension rat model. In addition, we determined whether dysregulation of the ADMA-metabolizing enzyme dimethylarginine dimethylaminohydrolase I (DDAH I) plays a role in this disease.

Methods and Results—

Adult male rats were exposed for 1 week to either normoxia or hypoxia (10% oxygen). Lung tissues were used for Western blot analysis of endothelial NOS and DDAH I expression, measurement of lung NO and ADMA content, and in vitro assay of DDAH enzyme activity. Western blot analysis revealed a 1.9-fold increase in endothelial NOS protein and a 37% decrease in DDAH I protein in the lungs of hypoxia-exposed rats. Both pulmonary DDAH enzyme activity and NO content were significantly decreased in the hypoxic group (by 37% and 22%, respectively), but pulmonary ADMA concentrations were increased by 2.3-fold compared with the normoxic group.

Conclusions—

These data demonstrate that the rat chronic hypoxia–induced pulmonary hypertension model is associated with increased pulmonary concentrations of the NOS inhibitor ADMA. Moreover, pulmonary hypertensive rats exhibit reduced pulmonary expression and activity of the ADMA-metabolizing enzyme DDAH I. The decreased DDAH I and increased ADMA concentrations may therefore contribute to pulmonary hypertension via the competitive inhibition of pulmonary NOS enzymes.
Long-Term Survival After Surgical Treatment of Patients With Takayasu’s Arteritis
Authors: Miyata Tetsuro , Sato Osamu , Koyama Hiroyuki , Shigematsu Hiroshi , Tada Yusuke
Published: September 2003

Background—

Surgical interventions have been performed to ameliorate the complications of Takayasu’s arteritis. However, the efficacy of surgery to increase long-term survival has not been established.

Methods and Results—

A retrospective review was performed on the survival of 106 consecutive patients with Takayasu’s arteritis who underwent surgical treatment during the past 40 years. Their ages ranged from 5 to 69 years (mean±SEM, 31.7±1.3 years). Survival was compared with the reported results of medically treated patients according to Ishikawa’s prognostic classification. There were 12 hospital deaths, and the remaining 94 patients were followed up from 8 months to 41.8 years (mean, 19.8 years). A serious long-term complication was anastomotic aneurysm, with a cumulative incidence at 20 years of 13.8%. Thirty-one late deaths were observed, and the major cause was congestive heart failure. The overall cumulative survival rate at 20 years was 73.5%. The prognostic classification by Ishikawa had little influence on the survival of surgically treated patients. For stage 3 patients, surgery seemed to increase survival; however, surgery-related complications conversely decreased the survival of stage 1 patients.

Conclusions—

Surgery seems to increase the long-term survival of patients with stage 3 Takayasu’s arteritis, whereas conservative treatment is recommended for those with stage 1 or 2 disease. An anastomotic aneurysm may occur at any time after surgery, and regular follow-up using imaging modalities such as multi-detector CT, MRI, or ultrasonography at least once every several years for the rest of the patient’s life is mandatory for the early detection of anastomotic aneurysm.
Early Short-Term Treatment With Doxycycline Modulates Postinfarction Left Ventricular Remodeling
Authors: Villarreal Francisco J. , Griffin Michael , Omens Jeffrey , Dillmann Wolfgang , Nguyen Judy , Covell James
Published: September 2003

Background—

Myocardial infarction (MI) is associated with early metalloproteinase (MMP) activation and extracellular matrix (ECM) degradation. We hypothesized that preserving the original ECM of the infarcted left ventricle (LV) by use of early short-term doxycycline (DOX) treatment preserves cardiac structure and function.

Methods and Results—

LV morphometry and function were measured in 3 groups of rats (sham, MI, and MI+DOX). DOX (30 mg/kg per day) was given orally 48 hours before and 48 hours after MI. Rats were examined at 2 and 4 weeks after MI. By 4 weeks, DOX significantly decreased (
P
<0.05 versus MI) the heart weight to body weight ratio, myocyte cross-sectional area, and internal LV diameter, whereas it preserved anterior wall thickness within the infarct. Collagen/muscle area fraction did not change in the region of the infarct/scar. Parallel left shifts (versus MI) were observed in pressure-volume relationships of DOX MI rats at all pressures. DOX treatment also shifted passive epicardial strains within the scar area toward normal values. No differences were observed in LV end-diastolic or peak systolic pressures, peak positive or negative LV dP/dt, or isovolumic relaxation rates. Assessment of LV global MMP and MMP-2/9 activities 1 hour after MI using fluorescent probes yielded significant differences with DOX.

Conclusions—

Brief, early MMP inhibition after MI yields preservation of LV structure and global as well as scar area passive function, supporting the concept that preserving the original ECM early after coronary occlusion lessens ventricular remodeling.
Serum Amyloid A in Obstructive Sleep Apnea
Authors: Svatikova Anna , Wolk Robert , Shamsuzzaman Abu S. , Kara Tomas , Olson Eric J. , Somers Virend K.
Published: September 2003

Background—

Patients with severe obstructive sleep apnea (OSA) may have increased risk for cardiovascular and cerebrovascular diseases. Serum amyloid A (SAA) protein has recently been linked to the development of atherosclerosis, stroke, diabetes, and dementia. We tested the hypothesis that plasma SAA levels are increased in otherwise healthy subjects with OSA.

Methods and Results—

Plasma SAA levels were measured in 10 male patients with moderate to severe OSA before sleep, after 5 hours of untreated OSA, and in the morning after effective continuous positive airway pressure treatment. SAA levels were also measured in 10 closely matched control subjects at similar time points. Baseline plasma SAA levels before sleep were strikingly higher in patients with moderate to severe OSA than in controls (18.8±2.6 versus 7.2±2.6 μg/mL, respectively;
P
=0.005) and remained unchanged in both groups throughout the night. SAA levels in 10 male patients with mild OSA were comparable with controls (
P
=0.46). Plasma SAA in 7 female patients with moderate to severe OSA was also markedly higher compared with matched control female subjects (24.1±2.4 versus 10.2±2.4 μg/mL, respectively;
P
=0.0013) but was not different from male patients with moderate to severe OSA (
P
=0.3). There was a significant positive correlation between SAA and apnea-hypopnea index (
r
=0.40,
P
=0.03).

Conclusions—

Plasma SAA levels are more than 2-fold greater in patients with moderate to severe OSA compared with subjects with mild OSA or healthy controls regardless of gender. Elevated SAA may contribute to any increased risk for cardiovascular and neuronal dysfunction in patients with OSA.
Microdystrophin Gene Therapy of Cardiomyopathy Restores Dystrophin-Glycoprotein Complex and Improves Sarcolemma Integrity in the
Mdx
Mouse Heart
Authors: Yue Yongping , Li Zhenbo , Harper Scott Q. , Davisson Robin L. , Chamberlain Jeffrey S. , Duan Dongsheng
Published: September 2003

Background—

More than 90% of Duchenne muscular dystrophy (DMD) patients develop cardiomyopathy, and many die of cardiac failure. Despite tremendous progress in skeletal muscle gene therapy, few attempts have been made to treat cardiomyopathy. Microdystrophin genes are shown to correct skeletal muscle pathological lesions in the
mdx
mouse model for DMD. Here, we tested the therapeutic potential of adeno-associated virus (AAV)–mediated microdystrophin gene therapy in the
mdx
mouse heart.

Methods and Results—

AAV was delivered to the newborn
mdx
mouse cardiac cavity. The procedure was rapid and well tolerated. Efficient expression was achieved in the inner and the outer layers of the myocardium. The ubiquitous cytomegalovirus promoter resulted in substantially higher expression than the muscle-specific CK6 promoter. The therapeutic effects of microdystrophin were evaluated at 10 months after infection. Immunostaining demonstrated extensive microdystrophin expression and successful restoration of the dystrophin-glycoprotein complex. Importantly, AAV-mediated microdystrophin expression improved the sarcolemma integrity in the
mdx
heart.

Conclusions—

We established a simple gene transfer method for efficient and persistent transduction of the
mdx
mouse heart. AAV-mediated microdystrophin expression restored the critical dystrophin-glycoprotein complex and improved sarcolemma integrity of the
mdx
heart. Our results revealed the promise of AAV-microdystrophin gene therapy for cardiomyopathy in DMD.
Advanced Glycation End Products Stimulate an Enhanced Neutrophil Respiratory Burst Mediated Through the Activation of Cytosolic Phospholipase A
2
and Generation of Arachidonic Acid
Authors: Wong Richard K.M. , Pettit Andrew I. , Quinn Paulene A. , Jennings Sonja C. , Davies Joan E. , Ng Leong L.
Published: September 2003

Background—

Advanced glycation end products (AGEs) enhance NADPH oxidase, and hence respiratory burst activity, of stimulated neutrophils. They are thus potentially vasculopathic, especially in diabetes, uremia, and aging, in which AGEs classically accumulate. We investigated the underlying mechanisms.

Methods and Results—

Neutrophils prelabeled with [
3
H]arachidonic acid display increased [
3
H]arachidonate release on exposure to AGE-albumin over exposure to albumin alone (by 151±16%,
P
<0.01). Arachidonic acid (AA) itself seems to mediate the AGE-augmented neutrophil respiratory burst (ascertained by chemiluminescence). Inhibitors of the cyclooxygenase pathway (indomethacin) and lipoxygenase pathway (MK-886) do not impair this AGE effect, excluding a contribution from AA metabolites. Cytosolic phospholipase A
2
(cPLA
2
) controls AA generation. Its inhibition by methyl arachidonyl fluorophosphonate abrogates the AGE-enhanced activated neutrophil respiratory burst, and it is demonstrably stimulated in AGE-exposed neutrophils, as evidenced by isoform gel-shift and an increasingly membrane-translocated state in Western blots of neutrophil subfractions. Inhibition of other PLA
2
isoforms, secretory PLA
2
and calcium-independent PLA
2
, by manoalide and haloenol-lactone suicide substrate, respectively, does not affect this effect of AGEs relative to inhibitor-treated controls. The thiol antioxidant NAC reduces activation of cPLA
2
(assessed by isoform gel-shift and membrane translocation), production of AA in AGE-albumin–exposed neutrophils (H
3
release reduced to 104±17%,
P
=0.94 compared with albumin-exposed neutrophils), and the AGE-augmented neutrophil respiratory burst.

Conclusions—

AGE augmentation of the activated neutrophil respiratory burst requires AA generation, through which neutrophil NADPH oxidase may be upregulated, enhancing reactive oxygen species output. AA is generated by cPLA
2
, which may be stimulated through an AGE-activated redox-sensitive pathway.
Myocardial Collagen Turnover in Hypertrophic Cardiomyopathy
Authors: Lombardi Raffaella , Betocchi Sandro , Losi Maria Angela , Tocchetti Carlo Gabriele , Aversa Mariano , Miranda Marianna , D’Alessandro Gianluigi , Cacace Alessandra , Ciampi Quirino , Chiariello Massimo
Published: September 2003

Background—

Myocardial interstitial fibrosis is a characteristic of hypertrophic cardiomyopathy (HCM). This study evaluates the collagen turnover in HCM and its impact on left ventricular (LV) diastolic function.

Methods and Results—

Thirty-six HCM patients and 14 sex- and age-matched controls were studied. Collagen turnover was assessed as follows. By radioimmunoassay, a byproduct of collagen III synthesis (PIIINP) and 3 peptides resulting from collagen I synthesis (PICP and PINP) and degradation (ICTP) were measured. By ELISA, matrix metalloproteinases (MMPs) were determined, as follows: active MMP-2; active MMP-9; and MMP-1 as active, free (as active MMP-1 plus its precursor), and total (as free MMP-1 plus MMP-1/tissue inhibitor complexes). Tissue inhibitor of metalloproteinases-1 (TIMP-1) was also assayed. All patients underwent echocardiography. The difference in duration between transmitral forward (A) and pulmonary venous retrograde (AR) waves (A−Ar) was considered an estimate of passive diastolic function. Furthermore, restrictive or pseudonormal LV filling patterns were considered to identify patients with passive diastolic dysfunction. Patients had higher levels of PIIINP, ICTP, MMP-2, MMP-9, and total TIMP-1 than did controls. PIIINP was inversely related to LV end-diastolic diameter. A−Ar was inversely related to PICP, PINP, and their differences with ICTP (estimates of collagen I buildup). Furthermore, A−Ar was directly related to MMP-1 and MMP-2.

Conclusions—

As compared with controls, collagen turnover is enhanced in HCM patients. As collagen I synthesis prevails over degradation and MMP-1 and MMP-2 are inhibited, passive diastolic dysfunction occurs in patients with HCM.