bluuebunny/crossref_metadata_2025 huggingface dataset:
Micro–Positron Emission Tomography Imaging of Cardiac Gene Expression in Rats Using Bicistronic Adenoviral Vector-Mediated Gene Delivery
Authors: Chen Ian Y. , Wu Joseph C. , Min Jung-Jun , Sundaresan Gobalakrishnan , Lewis Xiaoman , Liang Qianwa , Herschman Harvey R. , Gambhir Sanjiv S.
Published: March 2004

Background—

We have previously validated the use of micro-positron emission tomography (microPET) for monitoring the expression of a single PET reporter gene in rat myocardium. We now report the use of a bicistronic adenoviral vector (Ad-CMV-D2R80a-IRES-HSV1-sr39tk) for linking the expression of 2 PET reporter genes, a mutant rat dopamine type 2 receptor (D2R80a) and a mutant herpes simplex virus type 1 thymidine kinase (HSV1-sr39tk), with the aid of an internal ribosomal entry site (IRES).

Methods and Results—

Rat H9c2 cardiomyoblasts transduced with increasing titers of Ad-CMV-D2R80a-IRES-HSV1-sr39tk (0 to 2.5×10
8
pfu) were assayed 48 hours later for reporter protein activities, which were found to correlate well with viral titer (
r
2
=0.96,
P
<0.001 for D2R80A;
r
2
=0.98,
P
<0.001 for HSV1-sr39TK) and each other (
r
2
=0.97;
P
<0.001). Experimental (n=8) and control (n=6) athymic rats underwent intramyocardial injection of up to 2×10
9
pfu of Ad-CMV-D2R80a-IRES-HSV1-sr39tk and saline, respectively. Forty-eight hours later and weekly thereafter, rats were assessed for D2R80a-dependent myocardial accumulation of 3-(2-[
18
F]fluoroethyl)spiperone ([
18
F]-FESP) and HSV1-sr39tk–dependent sequestration of 9-(4-[
18
F]fluoro-3-hydroxymethylbutyl)guanine ([
18
F]-FHBG) using microPET. Longitudinal [
18
F]-FESP and [
18
F]-FHBG imaging of experimental rats revealed a good correlation between the cardiac expressions of the 2 PET reporter genes (
r
2
=0.73;
P
<0.001). The location of adenovirus-mediated transgene expression, as inferred from microPET images, was confirmed by ex vivo gamma counting of explanted heart.

Conclusions—

The IRES-based bicistronic adenoviral vector can potentially be used in conjunction with PET for indirect imaging of therapeutic gene expression by replacing 1 of the 2 PET reporter genes with a therapeutic gene of choice.
β
3
-Integrin Mediates Smooth Muscle Cell Accumulation in Neointima After Carotid Ligation in Mice
Authors: Choi Eric T. , Khan M. Faisal , Leidenfrost Jeremy E. , Collins Emily T. , Boc Kenneth P. , Villa Brian R. , Novack Deborah V. , Parks William C. , Abendschein Dana R.
Published: March 2004

Background—

Pharmacological blockade of β
3
-integrins inhibits neointimal lesion formation in nonmouse animal models of arterial injury. In contrast, β
3
-integrin–deficient (β
3
−/−
) mice are not protected from neointimal lesion formation after arterial injury. We investigated this discrepancy in β
3
−/−
and wild-type (β
3
+/+
) mice using different models of injury.

Methods and Results—

After disruption of the carotid with a transluminal probe, there was no significant difference in neointimal thickening between β
3
−/−
and β
3
+/+
mice. However, after ligation of the carotid without medial disruption, there was reduced neointimal thickening in β
3
−/−
mice compared with β
3
+/+
mice at intervals up to 3 months. Lesion reduction in β
3
−/−
mice was associated with fewer intimal smooth muscle cells (SMCs) without a difference in SMC apoptosis or proliferation rate compared with β
3
+/+
mice, consistent with reduced SMC migration from the media into the intima of β
3
−/−
mice. Moreover, combined eccentric medial disruption and ligation of the carotid in β
3
−/−
mice resulted in neointimal lesion formation only at the site of medial disruption. Transplantation of bone marrow cells harvested from β
3
+/+
mice into irradiated β
3
−/−
mice resulted in reduced neointimal lesion formation after carotid ligation injury, confirming the importance of α
v
β
3
and not α
IIb
β
3
in the attenuated response.

Conclusions—

The α
v
β
3
-integrin mediates intimal SMC accumulation that contributes to neointimal thickening in the setting of arterial ligation.
Electrophysiological and Electroanatomic Characterization of the Atria in Sinus Node Disease
Authors: Sanders Prashanthan , Morton Joseph B. , Kistler Peter M. , Spence Steven J. , Davidson Neil C. , Hussin Azlan , Vohra Jitendra K. , Sparks Paul B. , Kalman Jonathan M.
Published: March 2004

Background—

The normal sinus pacemaker complex is an extensive structure within the right atrium. We hypothesized that patients with sinus node disease (SND) would have evidence of diffuse atrial abnormalities.

Methods and Results—

Sixteen patients with symptomatic SND and 16 age-matched controls were studied. The following were evaluated: effective refractory periods (ERPs) from the high and low lateral right atrium (RA), high septal RA, and distal coronary sinus (CS); conduction time along the CS and lateral RA; P-wave duration; and conduction at the crista terminalis. Electroanatomic mapping was performed to define the sinus node complex and determine regional conduction velocity, double potentials, fractionated electrograms, regional voltage, and areas of electrical silence. Patients with SND demonstrated significant increase in atrial ERP at all right atrial sites, increased atrial conduction time along the lateral RA and CS, prolongation of the P-wave duration, and greater number and duration of double potentials along the crista terminalis. Electroanatomic mapping demonstrated the sinus node complex in SND to be more often unicentric, localized to the low crista terminalis at the site of the largest residual voltage amplitude. There was significant regional conduction slowing with double potentials and fractionation associated with areas of low voltage and electrical silence (or scar).

Conclusions—

SND is associated with diffuse atrial remodeling characterized by structural change, conduction abnormalities, and increased right atrial refractoriness. There was a change in the nature of sinus pacemaker activity with loss of the normal multicentric pattern of activation, caudal shift of the pacemaker complex, and abnormal and circuitous conduction around lines of conduction block.
Relationships Between Sinus Rhythm, Treatment, and Survival in the Atrial Fibrillation Follow-Up Investigation of Rhythm Management (AFFIRM) Study
Authors:   The AFFIRM Investigators
Published: March 2004

Background—

The AFFIRM Study showed that treatment of patients with atrial fibrillation and a high risk for stroke or death with a rhythm-control strategy offered no survival advantage over a rate-control strategy in an intention-to-treat analysis. This article reports an “on-treatment” analysis of the relationship of survival to cardiac rhythm and treatment as they changed over time.

Methods and Results—

Modeling techniques were used to determine the relationships among survival, baseline clinical variables, and time-dependent variables. The following baseline variables were significantly associated with an increased risk of death: increasing age, coronary artery disease, congestive heart failure, diabetes, stroke or transient ischemic attack, smoking, left ventricular dysfunction, and mitral regurgitation. Among the time-dependent variables, the presence of sinus rhythm (SR) was associated with a lower risk of death, as was warfarin use. Antiarrhythmic drugs (AADs) were associated with increased mortality only after adjustment for the presence of SR. Consistent with the original intention-to-treat analysis, AADs were no longer associated with mortality when SR was removed from the model.

Conclusions—

Warfarin use improves survival. SR is either an important determinant of survival or a marker for other factors associated with survival that were not recorded, determined, or included in the survival model. Currently available AADs are not associated with improved survival, which suggests that any beneficial antiarrhythmic effects of AADs are offset by their adverse effects. If an effective method for maintaining SR with fewer adverse effects were available, it might be beneficial.
Implantable Cardioverter/Defibrillator Therapy in Arrhythmogenic Right Ventricular Cardiomyopathy
Authors: Wichter Thomas , Paul Matthias , Wollmann Christian , Acil Tayfun , Gerdes Petra , Ashraf Obaidullah , Tjan Tonny D.T. , Soeparwata Rasijd , Block Michael , Borggrefe Martin , Scheld Hans H. , Breithardt Günter , Böcker Dirk
Published: March 2004

Background—

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a major cause of ventricular tachycardia (VT) and cardiac arrest in young patients. We hypothesized that treatment with implantable cardioverter/defibrillators (ICDs) is safe and improves the long-term prognosis of ARVC patients at high risk of sudden death.

Methods and Results—

Sixty patients with ARVC (aged 43±16 years) were treated with transvenous ICD systems. Despite a higher number of right ventricular sites tested for adequate lead positions (
P
<0.05), lower R-wave amplitudes (
P
<0.001) were achieved in ARVC patients compared with other entities. During follow-up of 80±43 months (396 patient-years), event-free survival was 49%, 30%, 26%, and 26% for appropriate ICD therapies and 79%, 64%, 59%, and 56% for potentially fatal VT (>240 bpm) after 1, 3, 5, and 7 years, respectively. Multivariate analysis identified extensive right ventricular dysfunction as an independent predictor of appropriate ICD discharge. Fifty-three adverse events occurred in 37 patients during the perioperative (n=10) or follow-up (n=43) period, mainly related to the leads (n=31 in 21 patients). No lead perforation was observed. Freedom from adverse events was 90%, 78%, 56%, and 42% and freedom from lead-related complications was 95%, 85%, 74%, and 63% after 1, 3, 5, and 7 years, respectively.

Conclusions—

These results strongly suggest an improvement in long-term prognosis by ICD therapy in high-risk patients with ARVC. However, meticulous placement and long-term observation of transvenous lead performance with focus on sensing function are required for the prevention and/or early recognition of disease progression and lead-related morbidity during long-term follow-up of ICD therapy in ARVC.
Beneficial Effects of Clopidogrel Combined With Aspirin in Reducing Cerebral Emboli in Patients Undergoing Carotid Endarterectomy
Authors: Payne David A. , Jones Chris I. , Hayes Paul D. , Thompson Matthew M. , London Nicholas J. , Bell Peter R. , Goodall Alison H. , Naylor A. Ross
Published: March 2004

Background—

Postoperative thromboembolic stroke affects 2% to 3% of patients undergoing carotid endarterectomy (CEA) and is preceded by 1 to 2 hours of increasing cerebral embolization. Previous work has demonstrated that high rates of postoperative embolization are associated with increased platelet reactivity to adenosine 5′-diphosphate (ADP). Our hypothesis was that preoperative administration of the platelet ADP antagonist clopidogrel could reduce postoperative embolization.

Methods and Results—

One hundred CEA patients on routine aspirin therapy (150 mg) were randomized to 75 mg clopidogrel (n=46) or placebo (n=54) the night before surgery. Platelet response to ADP was assessed by whole-blood flow cytometry. The number of emboli detected by transcranial Doppler within 3 hours of CEA was independently quantified. Time taken from flow restoration to skin closure was used as an indirect measure of the time to secure hemostasis. In comparison with placebo, clopidogrel produced a small (8.8%) but significant reduction in the platelet response to ADP (
P
<0.05) while conferring a 10-fold reduction in the relative risk of those patients having >20 emboli in the postoperative period (odds ratio, 10.23; 95% CI, 1.3 to 83.3;
P
=0.01, Fisher’s exact test). However, in the clopidogrel-treated patients, the time from flow restoration to skin closure (an indirect marker of hemostasis) was significantly increased (
P
=0.04, Fisher’s exact test), although there was no increase in bleeding complications or blood transfusions.

Conclusions—

This is the first study to show that a CEA patient’s postoperative thromboembolic potential can be significantly reduced by targeted preoperative antiplatelet therapy without increasing the risk of bleeding complications.
Tight Glycemic Control in Diabetic Coronary Artery Bypass Graft Patients Improves Perioperative Outcomes and Decreases Recurrent Ischemic Events
Authors: Lazar Harold L. , Chipkin Stuart R. , Fitzgerald Carmel A. , Bao Yusheng , Cabral Howard , Apstein Carl S.
Published: March 2004

Background—

This study sought to determine whether tight glycemic control with a modified glucose-insulin-potassium (GIK) solution in diabetic coronary artery bypass graft (CABG) patients would improve perioperative outcomes.

Methods and Results—

One hundred forty-one diabetic patients undergoing CABG were prospectively randomized to tight glycemic control (serum glucose, 125 to 200 mg/dL) with GIK or standard therapy (serum glucose <250 mg/dL) using intermittent subcutaneous insulin beginning before anesthesia and continuing for 12 hours after surgery. GIK patients had lower serum glucose levels (138±4 versus 260±6 mg/dL;
P
<0.0001), a lower incidence of atrial fibrillation (16.6% versus 42%;
P
=0.0017), and a shorter postoperative length of stay (6.5±0.1 versus 9.2±0.3 days;
P
=0.003). GIK patients also showed a survival advantage over the initial 2 years after surgery (
P
=0.04) and decreased episodes of recurrent ischemia (5% versus 19%;
P
=0.01) and developed fewer recurrent wound infections (1% versus 10%,
P
=0.03).

Conclusions—

Tight glycemic control with GIK in diabetic CABG patients improves perioperative outcomes, enhances survival, and decreases the incidence of ischemic events and wound complications.
Novel Oral Formulation of Paclitaxel Inhibits Neointimal Hyperplasia in a Rat Carotid Artery Injury Model
Authors: Kim Dong-Woon , Kwon Jin-Sook , Kim Young-Gyu , Kim Maeng Sup , Lee Gwan-Sun , Youn Tae-Jin , Cho Myeong-Chan
Published: March 2004

Background—

Paclitaxel has been shown to inhibit vascular smooth muscle cell migration and proliferation contributing to neointimal formation. This study tested whether novel oral formulations of paclitaxel can prevent neointimal formation in a rat carotid artery injury model.

Methods and Results—

Oral formulations of paclitaxel (0, 5, 7.5, or 10 mg/kg) were administered to 40 rats by gavage for 5 days after injury. The peak plasma levels of paclitaxel administered at 5, 7.5, and 10 mg/kg were 61±16, 89±22, and 108±28 nmol/L, respectively. Treatment effects were assessed 11 days after injury. The angiographic minimum luminal diameters of the oral paclitaxel groups treated at 5, 7.5, and 10 mg/kg were 6.28±2.09, 6.97±1.79, and 7.97±1.57 AU, and these were significantly larger than that of the control group (4.67±1.45 AU). The oral paclitaxel groups (5, 7.5, 10 mg/kg; 0.05±0.05, 0.04±0.03, 0.05±0.03 mm
2
) showed significant neointimal formation reductions versus the control group (0.13±0.05 mm
2
). All rats survived to study completion. Only 2 animals in the 10 mg/kg group experienced weight loss (≈10%) and loose stools between 4 and 6 days after injury. All other animals appeared healthy during the study. For comparison purposes, intraperitoneal formulations of paclitaxel (0 or 2 mg/kg) were administered by injection to 15 rats. We confirmed that the intraperitoneal administration of paclitaxel also effectively inhibited neointimal formation.

Conclusions—

Oral formulations of paclitaxel provide an effective means of inhibiting proliferative response to vascular injury in the rat. Thus, oral formulations of paclitaxel may prevent human restenosis without significant toxicity.
Left Ventricular Concentric Geometry During Treatment Adversely Affects Cardiovascular Prognosis in Hypertensive Patients
Authors: Muiesan Maria Lorenza , Salvetti Massimo , Monteduro Cristina , Bonzi Bianca , Paini Anna , Viola Sara , Poisa Paolo , Rizzoni Damiano , Castellano Maurizio , Agabiti-Rosei Enrico
Published: March 2004

Left ventricular (LV) mass and geometry predict risk for cardiovascular events in hypertension. Regression of LV hypertrophy (LVH) may imply an important prognostic significance. The relation between changes in LV geometry during antihypertensive treatment and subsequent prognosis has not yet been determined. A total of 436 prospectively identified uncomplicated hypertensive subjects with a baseline and follow-up echocardiogram (last examination 72±38 months apart) were followed for an additional 42±16 months. Their family doctor gave antihypertensive treatment. After the last follow-up echocardiogram, a first cardiovascular event occurred in 71 patients. Persistence of LVH from baseline to follow-up was confirmed as an independent predictor of cardiovascular events. Cardiovascular morbidity and mortality were significantly greater in patients with concentric (relative wall thickness ≥0.44) than in those with eccentric geometry (relative wall thickness <0.44) in patients presenting with LVH (
P
=0.002) and in those without LVH (
P
=0.002) at the follow-up echocardiogram. The incidence of cardiovascular events progressively increased from the first to the third tertile of LV mass index at follow-up (partition values 91 and 117 g/m
2
), but for a similar value of LV mass index it was significantly greater in those with concentric geometry (OR: 4.07; 95% CI: 1.49 to 11.14;
P
=0.004 in the second tertile; OR: 3.45; 95% CI: 1.62 to 7.32;
P
=0.001 in the third tertile;
P
<0.0001 in concentric versus eccentric geometry). Persistence or development of concentric geometry during follow-up may have additional prognostic significance in hypertensive patients with and without LVH.
Sgk1 Mediates Osmotic Induction of NPR-A Gene in Rat Inner Medullary Collecting Duct Cells
Authors: Chen Songcang , McCormick James A. , Prabaker Kavitha , Wang Jian , Pearce David , Gardner David G.
Published: March 2004

We have shown previously that increased extracellular osmolality stimulates expression and promoter activity of the type A natriuretic peptide receptor (NPR-A) gene in rat inner medullary collecting duct (IMCD) cells through a mechanism that involves activation of p38 mitogen-activated protein kinase (MAPK). The serum and glucocorticoid inducible kinase (Sgk) is thought to participate in the regulation of sodium handling in distal tubular segments. We sought to determine whether this kinase might be involved in the osmotic stimulation of NPR-A gene promoter activity. Exposure of cultured IMCD cells to an additional 75 mmol/L NaCl in culture media (final osmolality 475 mosm/kg) resulted in an ≈4-fold increase in Sgk1 protein levels after 7 hours. The Sgk1 induction was almost completely inhibited by the p38 MAPK inhibitor SB203580, indicating that NaCl activates Sgk1 through the p38 MAPK pathway. Transient transfection of a mouse Sgk1 expression vector along with a −1590 NPR-A luciferase reporter resulted in an ≈3-fold increment in reporter activity, which was significantly reduced by cotransfection with a kinase-dead Sgk1 mutant. The NaCl-dependent induction was partially blocked (≈40% inhibition) by cotransfection of the kinase-dead Sgk1 mutant. Neither Sgk1 nor the kinase-dead mutant had any effect on endothelial nitric oxide synthase (eNOS) promoter activity, and the Sgk1 mutant and 8-bromo-cyclic guanosine monophosphate were, to some degree, additive in reducing osmotically stimulated NPR-A promoter activity. Collectively, these data imply that Sgk1 operates over an eNOS-independent, p38 MAPK-dependent pathway in mediating osmotic induction of the NPR-A gene promoter.
Effects of Indapamide, a Thiazide-Like Diuretic, on Structure of Cerebral Arterioles in Hypertensive Rats
Authors: Chillon Jean-Marc , Baumbach Gary L.
Published: March 2004

We examined the effects of indapamide, a thiazide-like diuretic, on cerebral arterioles in spontaneously hypertensive rats (SHR). The structure and mechanics of cerebral arterioles were examined in untreated Wistar Kyoto rats (WKY) and SHR that were untreated or treated for 3 months with a low (1 mg/kg per day) or a high (10 mg/kg per day) dose of indapamide. We measured pressure, diameter, and cross-sectional area of the vessel wall (CSA) in maximally-dilated (EDTA) cerebral arterioles. Treatment of SHR with the high dose of indapamide normalized cerebral arteriolar mean pressure (62±4 [mean±SEM] versus 59±3 mm Hg in WKY and 88±6 mm Hg in untreated SHR;
P
<0.05), pulse pressure (13±1 versus 10±1 mm Hg in WKY and 20±1 mm Hg in untreated SHR;
P
<0.05), and CSA (1080±91 versus 1100±48 μm
2
in WKY and 1439±40 μm
2
in untreated SHR;
P
<0.05). In contrast, treatment of SHR with the low dose of indapamide did not normalize arteriolar mean (72±3) and pulse pressure (20±1 mm Hg), but did normalize CSA (1091±52 μm
2
). Treatment with either dose of indapamide failed to increase external diameter in cerebral arterioles of SHR (89±4 and 92±4 μm, respectively, versus 103±6 μm in WKY and 87±4 μm in untreated SHR). Finally, treatment with indapamide attenuated the rightward shift of the stress-strain curve in SHR, suggesting that treatment with indapamide attenuated increases in distensibility of cerebral arterioles in SHR. These findings suggest that, whereas thiazide-like diuretics may not attenuate eutrophic inward remodeling of cerebral arterioles in SHR, they may attenuate hypertrophic inward remodeling via a mechanism unrelated to their pressor effects.
In Vivo Evaluation of Retinal Injury After Transient Ischemia in Hypertensive Rats
Authors: Hirose Fumitaka , Kiryu Junichi , Miyamoto Kazuaki , Nishijima Kazuaki , Miyahara Shinsuke , Katsuta Hideto , Tamura Hiroshi , Honda Yoshihito
Published: March 2004

A number of studies have suggested that hypertension affects the pathogenesis of inflammatory reactions in various organs. The objective of this study was to evaluate the effects of hypertension on leukocyte–endothelial interactions after transient retinal ischemia. Transient retinal ischemia was induced for 60 minutes in spontaneously hypertensive rats (SHR) and in age-matched normotensive Wistar-Kyoto rats (WKY). At 4, 12, 24, 48, and 72 hours after reperfusion, flat-mount retinas were prepared to evaluate the density of leukocytes that had been accumulated in the retina. Intercellular adhesion molecule-1 (ICAM-1) mRNA expression was studied by semiquantitative polymerase chain reaction and ICAM-1 protein levels were studied by enzyme-linked immunosorbent assay. At 14 days after reperfusion, the retinal damage and the effect of superoxide dismutase on the damage were evaluated histologically. In SHR, the number of accumulated leukocytes peaked at 48 hours after reperfusion, and it was upregulated to 5.2-fold, as compared with that of WKY (
P
<0.001). ICAM-1 mRNA expression and ICAM-1 protein levels were increased significantly in the ischemia-reperfused retina in SHR compared with WKY (
P
<0.05). Histological examination demonstrated marked increase in the retinal ischemia/reperfusion damage in SHR (
P
<0.01) and a significant amelioration of the damage by treatment with superoxide dismutase in SHR (
P
<0.05). Oxidative stress may thus be an important mechanism for the deterioration seen in ischemia/reperfusion injury in the SHR retina.
Modulation of the Inflammatory Response in Cardiovascular Disease
Authors: Granger D. Neil , Vowinkel Thorsten , Petnehazy Thomas
Published: March 2004

There is a growing body of evidence that inflammation might play an important role in the initiation and progression of cardiovascular diseases (CVDs). The designation of CVD as a chronic inflammatory process is further supported by evidence that the risk factors for CVD cause endothelial cells throughout the vascular tree to assume an inflammatory phenotype. These activated endothelial cells characteristically exhibit oxidative stress and increased adhesiveness for circulating leukocytes. Although initial efforts to define the mechanisms underlying the inflammatory phenotype in diseased endothelial cells have focused on the linkage between oxidative stress and adhesion molecule activation/expression, recent work has implicated a variety of additional factors that can modulate the magnitude and/or nature of the inflammatory responses in CVD. Platelets, angiotensin II, and the CD40/CD40 ligand signaling system are gaining recognition as contributors to the pathogenesis of CVD. These factors appear to converge with known pathways that link oxidative stress with adhesion molecule expression and help to explain the apparent integration of coagulation with inflammation in CVD. These factors also hold the promise of offering multiple sites for therapeutic intervention in CVD.
Broadly Altered Gene Expression in Blood Leukocytes in Essential Hypertension Is Absent During Treatment
Authors: Chon Helena , Gaillard Carlo A.J.M. , van der Meijden Brenda B. , Dijstelbloem Hilde M. , Kraaijenhagen Rob J. , van Leenen Dik , Holstege Frank C.P. , Joles Jaap A. , Bluyssen Hans A.R. , Koomans Hein A. , Braam Branko
Published: March 2004

We assessed whether large-scale expression profiling of leukocytes of patients with essential hypertension reflects characteristics of systemic disease and whether such changes are responsive to antihypertensive therapy. Total RNA from leukocytes were obtained from untreated (n=6) and treated (n=6) hypertensive patients without apparent end-organ damage and from normotensive controls (n=9). RNA was reverse-transcribed and labeled and gene expression analyzed using a 19-K oligonucleotide microarray using dye swaps. Samples of untreated and of treated patients were pooled for each sex and compared with age- and sex-matched controls. In untreated patients, 680 genes were differentially regulated (314 up and 366 down). In the treated patients, these changes were virtually absent (4 genes up, 3 genes down). A myriad of changes was observed in pathways involved in inflammation. Inflammation-dampening interleukin receptors were decreased in expression. Intriguingly, inhibitors of cytokine signaling (the PIAS family of proteins) were differentially expressed. The expression of several genes that are involved in regulation of blood pressure were also differentially expressed: angiotensin II type 1 receptor, ANP-A receptor, endothelin-2, and 3 of the serotonin receptors were increased, whereas endothelin-converting enzyme-1 was decreased. Strikingly, virtually no changes in gene expression could be detected in hypertensive patients who had become normotensive with treatment. This observation substantiates the long-standing idea that hypertension is associated with a complex systemic response involving inflammation-related genes. Furthermore, leukocytes display differential gene expression that is of importance in blood pressure control. Importantly, treatment of blood pressure to normal values can virtually correct such disturbances.
Hypertension and Insulin Resistance Are Not Directly Related in Obese Dogs
Authors: Rocchini Albert P. , Yang John Q. , Gokee Amy
Published: March 2004

In dogs fed a high-fat diet, we determined whether there was a direct relation between obesity-induced insulin resistance and obesity-induced hypertension. Thirty-six adult mongrel dogs were chronically instrumented and assigned to receive either a high-fat diet alone (n=7) or a high-fat diet combined with a low-sodium diet plus furosemide (n=6), prazosin plus atenolol (n=7), clonidine (n=10), or aspirin (n=6). Blood pressure, heart rate, and body weight were measured daily. Insulin resistance was assessed with a single-dose euglycemic hyperinsulinemic clamp (2 mU · kg
−1
· min
−1
) before and after 1, 3, and 6 weeks of the high-fat diet. The low-salt diet plus furosemide, prazosin plus atenolol, and clonidine treatments prevented the hypertension associated with feeding the dogs a high-fat diet. Only clonidine treatment totally prevented the development of insulin resistance, and high-dose aspirin, known to prevent insulin resistance by inhibition of the activity of IκB kinase-β, decreased the degree of insulin resistance by almost 70%. However, aspirin had no effect on the development of hypertension. We conclude that obesity-induced hypertension and obesity-induced insulin resistance are not directly related. In addition, there is a suggestion that insulin resistance in this experimental model is mediated through the central and or peripheral α
2
-adrenoceptors, whereas hypertension is mediated through the α
1
- and or β-adrenoceptors.
Angiotensin II–Induced Vascular Dysfunction Is Mediated by the AT
1A
Receptor in Mice
Authors: Ryan Michael J. , Didion Sean P. , Mathur Satya , Faraci Frank M. , Sigmund Curt D.
Published: March 2004

Many of the actions of angiotensin II (Ang II) are mediated by angiotensin type 1 receptors (AT
1
), of which there are 2 pharmacologically indistinguishable subtypes (AT
1A
and AT
1B
). The purpose of this study was to evaluate the effect of an AT
1A
homozygous deletion (AT
1A
−/−
) on vascular reactivity. AT
1A
−/−
mice and control littermates (AT
1A
+/+
) were infused with vehicle (saline) or Ang II (1000 ng · kg
−1
· min
−1
) for 7 days by osmotic pumps. Systolic pressure was increased in AT
1A
+/+
mice (Δ45±8 mm Hg,
P
<0.0001) but unchanged in AT
1A
−/−
mice (Δ5±3 mm Hg,
P
>0.13) on day 7. The carotid artery response to the vasodilators acetylcholine (ACh), nitroprusside, and papaverine and to the vasoconstrictors phenylephrine, U46619, 5-hydroxytryptamine (5-HT), and KCl were not different between vehicle-infused AT
1A
+/+
and AT
1A
−/−
animals. Carotid relaxation to ACh was impaired and contraction to 5-HT was increased in Ang II–infused AT
1A
+/+
mice. Ang II did not affect carotid responses in AT
1A
−/−
mice. Superoxide, measured by lucigenin (5 μmol/L), and hydroethidine staining were not different between AT
1A
+/+
and AT
1A
−/−
mice after vehicle or Ang II infusion, suggesting that it was not contributing to the altered ACh and 5-HT responses. The Rho-kinase inhibitor Y-27632 (1 μmol/L) attenuated the 5-HT response in both vehicle- and Ang II–infused AT
1A
+/+
mice. Moreover, concentration-dependent relaxation to Y-27632 and RhoA protein expression were not different in vehicle- or Ang II–infused AT
1A
+/+
. These data demonstrate that the AT
1A
receptor is required for Ang II–induced changes in carotid artery function.
Renal Interstitial Guanosine Cyclic 3′, 5′-Monophosphate Mediates Pressure-Natriuresis Via Protein Kinase G
Authors: Jin Xiao-Hong , McGrath Helen E. , Gildea John J. , Siragy Helmy M. , Felder Robin A. , Carey Robert M.
Published: March 2004

Pressure-natriuresis is the physiological protective mechanism whereby elevation of blood pressure induces a rapid increase in renal sodium (Na
+
) excretion. Pressure-natriuresis abnormalities are common to all forms of hypertension. We tested the hypothesis that pressure-natriuresis is mediated by renal interstitial (RI) cGMP and protein kinase G (PKG). We used anesthetized, uninephrectomized Sprague-Dawley rats and a standard pressure-natriuresis model in which bilateral adrenalectomy and renal denervation was done on rats. Renal perfusion pressure (RPP) was adjusted by manipulating clamps above and below the renal artery, and RI cGMP was quantified by microdialysis. RI cGMP increased from 3.1±0.5 to 5.5±0.4 fmol/min (
P
<0.05) when RPP was raised from 100 to 140 mm Hg. This increase in RI cGMP was eliminated by RI infusion of soluble guanylyl cyclase inhibitor 1H-[1,2,4]oxadiazolo[4,2-α]quinoxalin-1-one (ODQ). Raising RPP from 100 to 140 mm Hg increased urinary sodium excretion from 0.2±0.1 to 0.8±0.1 μmol/min, fractional sodium excretion from 0.2±0.1% to 0.8±0.1%, and fractional lithium excretion from 20.1±3.0% to 62.7±3.7% (all
P
<0.05). These responses were eliminated by RI infusion of nitric oxide synthase inhibitor
N
-nitro-
l
-arginine methyl ester, ODQ, and PKG inhibitors Rp-8-pCPT-cGMP and Rp-8-Br-cGMP. Increasing RPP from 100 to 140 mm Hg decreased fractional proximal sodium reabsorption without influencing fractional distal Na
+
reabsorption or glomerular filtration rate. In conclusion, pressure-natriuresis is mediated by RI cGMP and a PKG signaling pathway in target renal proximal tubule cells.
Relations of Serum Aldosterone to Cardiac Structure
Authors: Vasan Ramachandran S. , Evans Jane C. , Benjamin Emelia J. , Levy Daniel , Larson Martin G. , Sundstrom Johan , Murabito Joanne M. , Sam Flora , Colucci Wilson S. , Wilson Peter W. F.
Published: March 2004

Aldosterone is associated with myocardial fibrosis in experimental studies and with left ventricular remodeling in heart failure patients. We hypothesized that aldosterone influences ventricular remodeling in people without congestive heart failure in the community. We examined the relations between serum aldosterone and echocardiographic left ventricular measurements in 2820 Framingham Study subjects (mean age 57 years, 58% women, 88% white) free of myocardial infarction and overt heart failure. Serum aldosterone levels were higher in women compared with men. In linear regression models (adjusted for age, systolic blood pressure, weight, height, diabetes, heart rate, hypertension treatment, and ethnicity), left ventricular wall thickness and relative wall thickness were positively related, and left ventricular diastolic dimensions were inversely related to serum aldosterone in women (
P
<0.05 for all), but not in men (
P
>0.20 for all). There was no effect modification of the relations observed in women by menopausal status. The gender-related differences in relations of serum aldosterone to relative wall thickness were consistent across subgroups defined on the basis of sex-specific median values of systolic blood pressure and body mass index. Fractional shortening, left ventricular mass, and left atrial dimensions were not related to serum aldosterone in either sex. In conclusion, in our community-based sample of individuals free of myocardial infarction and heart failure, serum aldosterone was positively associated with a left ventricular geometric pattern suggestive of concentric remodeling (increased left ventricular wall thickness and relative wall thickness but decreased internal dimensions) in women but not in men. Additional investigations are warranted to confirm these findings.
Upregulation of Angiotensin-Converting Enzyme 2 After Myocardial Infarction by Blockade of Angiotensin II Receptors
Authors: Ishiyama Yuichiro , Gallagher Patricia E. , Averill David B. , Tallant E. Ann , Brosnihan K. Bridget , Ferrario Carlos M.
Published: March 2004

We investigated in Lewis normotensive rats the effect of coronary artery ligation on the expression of cardiac angiotensin-converting enzymes (ACE and ACE 2) and angiotensin II type-1 receptors (AT
1a
-R) 28 days after myocardial infarction. Losartan, olmesartan, or the vehicle (isotonic saline) was administered via osmotic minipumps for 28 days after coronary artery ligation or sham operation. Coronary artery ligation caused left ventricular dysfunction and cardiac hypertrophy. These changes were associated with increased plasma concentrations of angiotensin I, angiotensin II, angiotensin-(1–7), and serum aldosterone, and reduced AT
1a
-R mRNA. Cardiac ACE and ACE 2 mRNAs did not change. Both angiotensin II antagonists attenuated cardiac hypertrophy; olmesartan improved ventricular contractility. Blockade of the AT
1a
-R was accompanied by a further increase in plasma concentrations of the angiotensins and reduced serum aldosterone levels. Both losartan and olmesartan completely reversed the reduction in cardiac AT
1a
-R mRNA observed after coronary artery ligation while augmenting ACE 2 mRNA by approximately 3-fold. Coadministration of PD123319 did not abate the increase in ACE 2 mRNA induced by losartan. ACE 2 mRNA correlated significantly with angiotensin II, angiotensin-(1–7), and angiotensin I levels. These results provide evidence for an effect of angiotensin II blockade on cardiac ACE 2 mRNA that may be due to direct blockade of AT
1a
receptors or a modulatory effect of increased angiotensin-(1–7).
Evidence That IGF Binding Protein-5 Functions as a Ligand-Independent Transcriptional Regulator in Vascular Smooth Muscle Cells
Authors: Xu Qijin , Li Shenghua , Zhao Yang , Maures Travis J. , Yin Ping , Duan Cunming
Published: March 2004

Insulin-like growth factor binding protein (IGFBP)-5 is a conserved protein synthesized and secreted by vascular smooth muscle cells (VSMCs). IGFBP-5 binds to extracellular IGFs and modulates IGF actions in regulating VSMC proliferation, migration, and survival. IGFBP-5 also stimulates VSMC migration through an IGF-independent mechanism, but the molecular basis underlying this ligand-independent action is unknown. In this study, we show that endogenous IGFBP-5 or transiently expressed IGFBP-5-EGFP, but not IGFBP-4-EGFP, is localized in the nuclei of VSMCs. Using a series of IGFBP-4/5 chimeras and IGFBP-5 points mutants, we demonstrated that the IGFBP-5 C-domain is necessary and sufficient for its nuclear localization, and residues K206, K208, K217, and K218 are particularly critical. Intriguingly, inhibition of protein secretion abolishes IGFBP-5 nuclear localization, suggesting the nuclear IGFBP-5 is derived from the secreted protein. When added exogenously,
125
I- or Cy3-labeled IGFBP-5 is capable of cellular entry and nuclear translocation. To identify potential transcriptional factor(s) that interact with IGFBP-5, a human aorta cDNA library was screened by a yeast two-hybrid screening strategy. Although this screen identified many extracellular and cytosolic proteins that are known to interact with IGFBP-5, no known transcription factors were found. Further motif analysis revealed that the IGFBP-5 N-domain contains a putative transactivation domain. When fused to GAL-4 DNA dinging domain and tested, the IGFBP-5 N-domain has strong transactivation activity. Mutation of the IGF binding domain or treatment of cells with IGF-I has little effect on transactivation activity. These results suggest that IGFBP-5 is localized in VSMC nucleus and possesses transcription-regulatory activity that is IGF independent. The full text of this article is available online at http://circres.ahajournals.org.
Glucose Enhances Human Macrophage LOX-1 Expression
Authors: Li Ling , Sawamura Tatsuya , Renier Geneviève
Published: March 2004

Lectin-like oxidized LDL receptor-1 (LOX-1) is a newly identified receptor for oxidized LDL that is expressed by vascular cells. LOX-1 is upregulated in aortas of diabetic rats and thus may contribute to the pathogenesis of human diabetic atherosclerosis. In this study, we examined the regulation of human monocyte-derived macrophage (MDM) LOX-1 expression by high glucose and the role of LOX-1 in glucose-induced foam cell formation. Incubation of human MDMs with glucose (5.6 to 30 mmol/L) enhanced, in a dose- and time-dependent manner, LOX-1 gene and protein expression. Induction of LOX-1 gene expression by high glucose was abolished by antioxidants, protein kinase C (PKC), mitogen-activated protein kinases (MAPKs), nuclear factor-κB (NF-κB), and activated protein-1 (AP-1) inhibitors. In human MDMs cultured with high glucose, increased expression of PKCβ
2
and enhanced phosphorylation of extracellular signal-regulated protein kinase 1/2 was observed. Activation of these kinases was inhibited by the antioxidant
N
-acetyl-
l
-cysteine (NAC) and by the PKCβ inhibitor LY379196. High glucose also enhanced the binding of nuclear proteins extracted from human MDMs to the NF-κB and AP-1 regulatory elements of the LOX-1 gene promoter. This effect was abrogated by NAC and PKC/MAPK inhibitors. Finally, high glucose induced human macrophage-derived foam cell formation through a LOX-1–dependent pathway. Overall, these results demonstrate that high glucose concentrations enhance LOX-1 expression in human MDMs and that this effect is associated with foam cell formation. Pilot data showing that MDMs of patients with type 2 diabetes overexpress LOX-1 support the relevance of this work to human diabetic atherosclerosis.
Association of the
APOLIPOPROTEIN A1/C3/A4/A5
Gene Cluster With Triglyceride Levels and LDL Particle Size in Familial Combined Hyperlipidemia
Authors: Mar Rebecca , Pajukanta Päivi , Allayee Hooman , Groenendijk Martine , Dallinga-Thie Geesje , Krauss Ronald M. , Sinsheimer Janet S. , Cantor Rita M. , de Bruin Tjerk W.A. , Lusis Aldons J.
Published: March 2004

The
APOLIPOPROTEIN
(
APO
)
A1/C3/A4/A5
gene cluster on chromosome 11 has been hypothesized to be a modifier of plasma triglycerides in FCH. In the present study, we extended previous association analyses of the gene cluster to include
APOA5
, a newly discovered member of the cluster. Eight SNPs across the
APOA1/C3/A4/A5
gene region were analyzed in 78 FCH probands and their normolipidemic spouses as well as in 27 Dutch FCH families. Of the individual SNPs tested in the case-control panel, the strongest evidence of association was obtained with SNPs in
APOA1
(
P
=0.001) and
APOA5
(
P
=0.001). A single haplotype defined by a missense mutation in
APOA5
was enriched 3-fold in FCH probands when compared with the normolipidemic spouses (
P
=0.001) and a second haplotype was significantly enriched in the spouses (
P
=0.001). Family-based tests also indicated significant association of triglyceride levels and LDL particle size with the investigated SNPs of
APOC3
and
APOA5
. These findings suggest that genetic variation in the
APOA1/C3/A4/A5
gene cluster acts as a modifier of plasma triglyceride levels and LDL particle size within FCH families and furthermore indicate that a number of haplotypes may contribute to FCH.
Phosphorylation of Eukaryotic Translation Initiation Factor 2Bε by Glycogen Synthase Kinase-3β Regulates β-Adrenergic Cardiac Myocyte Hypertrophy
Authors: Hardt Stefan E. , Tomita Hideharu , Katus Hugo A. , Sadoshima Junichi
Published: March 2004

Glycogen synthase kinase 3β (GSK-3β) negatively regulates cardiac hypertrophy. A potential target mediating the antihypertrophic effect of GSK-3β is eukaryotic translation initiation factor 2Bε (eIF2Bε). Overexpression of GSK-3β increased the cellular kinase activity toward GST-eIF2Bε in neonatal rat cardiac myocytes, whereas LiCl (10 mmol/L) or isoproterenol (ISO) (10 μmol/L), a treatment known to inhibit GSK-3β, decreased it. Immunoblot analyses using anti-S535 phosphospecific eIF2Bε antibody showed that S535 phosphorylation of endogenous eIF2Bε was decreased by LiCl or ISO, suggesting that GSK-3β is the predominant kinase regulating phosphorylation of eIF2Bε-S535 in cardiac myocytes. Decreases in eIF2Bε-S535 phosphorylation were also observed in a rat model of cardiac hypertrophy in vivo. Overexpression of wild-type eIF2Bε alone moderately increased cell size (+31±11%;
P
<0.05 versus control), whereas treatment of eIF2Bε-transduced myocytes with LiCl (+73±22% versus eIF2Bε only;
P
<0.05) or ISO (+84±33% versus eIF2Bε only;
P
<0.05) enhanced the effect of eIF2Bε. Overexpression of eIF2Bε-S535A, which is not phosphorylated by GSK-3β, increased cell size (+107±35%) as strongly as ISO (+95±25%), and abolished antihypertrophic effects of GSK-3β, indicating that S535 phosphorylation of eIF2Bε critically mediates antihypertrophic effects of GSK-3β. Furthermore, expression of eIF2Bε-F259L, a dominant-negative mutant, inhibited ISO-induced hypertrophy, indicating that eIF2Bε is required for β-adrenergic hypertrophy. Interestingly, expression of eIF2Bε-S535A partially increased cytoskeletal reorganization, whereas it did not increase expression of atrial natriuretic factor gene. These results suggest that GSK-3β is the predominant kinase mediating phosphorylation of eIF2Bε-S535 in cardiac myocytes, which in turn plays an important role in regulating cardiac hypertrophy primarily through protein synthesis.
Heat Shock Protein 90α–Dependent Translocation of Annexin II to the Surface of Endothelial Cells Modulates Plasmin Activity in the Diabetic Rat Aorta
Authors: Lei Hetian , Romeo Giulio , Kazlauskas Andrius
Published: March 2004

The goals of this article were (1) to identify cell surface proteins whose expression was regulated by diabetes and (2) to assess their contribution to diabetic complications. We purified heat shock protein 90α (Hsp90α) from the membrane fraction of high glucose–treated endothelial cells (ECs) as a binding partner for a diabetes-specific phage. Further investigation revealed that high glucose elevated cell surface Hsp90α in cultured cells, and that diabetes increased the amount of Hsp90α on the luminal surface of the aorta. We also found that high glucose or diabetes promoted the association of Hsp90α with annexin II and increased the expression of annexin II on the surface of aortic ECs. Finally, plasmin activity was increased by high glucose or diabetes, and this change was partially reversed with an annexin II antibody. These findings reveal a novel glucose-regulated interaction between Hsp90α and annexin II, and raise the possibility that increased expression of annexin II, which promotes the generation of plasmin, is linked to clotting abnormalities associated with the diabetic state.
Evidence for Fusion Between Cardiac and Skeletal Muscle Cells
Authors: Reinecke Hans , Minami Elina , Poppa Veronica , Murry Charles E.
Published: March 2004

Cardiomyoplasty with skeletal myoblasts may benefit cardiac function after infarction. Recent reports indicate that adult stem cells can fuse with other cell types. Because myoblasts are “fusigenic” cells by nature, we hypothesized they might be particularly likely to fuse with cardiomyocytes. To test this, neonatal rat cardiomyocytes labeled with LacZ and green fluorescent protein (GFP) were cocultured with unlabeled C2C12 myoblasts. After 3 days, we observed a small population of skeletal myotubes that expressed LacZ and GFP, indicating cell fusion. To test whether such fusion occurred in vivo, LacZ-expressing C2C12 myoblasts were grafted into normal nude mouse hearts. At 2 weeks after grafting, cells at the graft-host interface expressed both LacZ and cardiac-specific myosin light chain 2v (MLC2v). To test more definitively whether fusion between skeletal and cardiac muscle could occur, we used a Cre/lox reporter system that activated LacZ only upon cell fusion. When neonatal cardiomyocytes from α-myosin heavy chain promoter (α-MHC)-Cre mice were cocultured with myoblasts from floxed-lacZ reporter mice, LacZ was activated in a subset of cells, indicating cell fusion occurred in vitro. Finally, we grafted the floxed-lacZ myoblasts into normal hearts of α-MHC-Cre
+
and α-MHC-Cre
−
mice (n=5 each). Hearts analyzed at 4 days and 1 week after transplantation demonstrated activation of LacZ when the skeletal muscle cells were implanted into hearts of α-MHC-Cre
+
mice, but not after implantation into α-MHC-Cre
−
mice. These data indicate that skeletal muscle cell grafting gives rise to a subpopulation of skeletal-cardiac hybrid cells with a currently unknown phenotype. The full text of this article is available online at
http://circres.ahajournals.org
.