Andrew P. Miller

Quantification of tricuspid regurgitation by live three-dimensional transthoracic echocardiographic measurements of vena contracta area.

We evaluated tricuspid regurgitation (TR) by multiple echocardiographic techniques in 93 consecutive patients who underwent standard two‐dimensional (2D) and live three‐dimensional (3D) transthoracic echocardiography (TTE). TR vena contracta (VC) area was obtained by 3D TTE by systematic and sequential cropping of the acquired 3D TTE dataset. Assessment of VC area by 3D TTE was compared to 2D TTE measurements of the ratio of TR regurgitant jet area to right atrial area (RJA/RAA), RJA alone, VC width, and calculated VC area. VC area from 3D TTE closely correlated with RJA/RAA and RJA alone as determined from 2D TTE measurements. Live 3D TTE color Doppler measurements of VC area can be used for quantitative assessment of TR and offer incremental value for quantification of particularly severe regurgitant lesions.

Estrogen Modulates Inflammatory Mediator Expression and Neutrophil Chemotaxis in Injured Arteries

Background—We have previously shown that estrogen (17&bgr;-estradiol; E2) inhibits neointima formation and migration of leukocytes, particularly neutrophils, into rat carotid arteries after acute endoluminal injury. This study tested the hypothesis that E2 inhibits expression of adhesion molecules, chemokines, and proinflammatory cytokines in rat carotid arteries in the early hours after balloon injury, thus attenuating the stimulus for leukocyte entry and negatively modulating the injury response. Methods and Results—Ovariectomized (OVX) rats were randomly assigned to treatment with E2 or vehicle (V) and subjected to balloon injury of the right carotid artery. After 2, 6, and 24 hours, rats were euthanized, and both carotid arteries were processed for real-time reverse transcription–polymerase chain reaction (2 and 24 hours), ELISA (6 hours), or neutrophil chemotaxis assay (24 hours). Expression of mRNA for adhesion molecules (P-selectin, vascular cell adhesion molecule-1, and intercellular adhesion molecule-1), chemoattractants (cytokine-induced neutrophil chemoattractant [CINC]-2&bgr; and monocyte chemoattractant protein [MCP]-1), and proinflammatory cytokines (interleukin [IL]-1 and IL-6) was markedly increased (2 to 5000 times) in injured arteries of OVX+V rats at 2 hours and was reduced by 24 hours. E2 significantly attenuated expression of the proinflammatory mediators (by 60% to 80%) at 2 hours. ELISA confirmed injury-induced upregulation of neutrophil and monocyte/macrophage chemoattractants (CINC-2&agr;, MCP-1) in OVX+V arteries and E2-induced inhibition of CINC-2&agr; expression. E2 significantly (by 65%) inhibited neutrophil chemotactic activity of arterial homogenates. Conclusions—E2 attenuates the early vascular injury response, at least in part, by negatively modulating proinflammatory mediator expression and the resultant chemotactic activity of injured vessels for neutrophils.

Assessment of Aortic Regurgitation by Live Three‐Dimensional Transthoracic Echocardiographic Measurements of Vena Contracta Area: Usefulness and Validation

In this report, we evaluate 56 consecutive adult patients who underwent standard two‐dimensional (2D) and live three‐dimensional transthoracic echocardiography (3D TTE), as well as left heart catheterization with aortography (45 patients) or cardiac surgery (11 patients), for evaluation of aortic insufficiency. Similar to the method we previously described for mitral insufficiency, aortic regurgitant vena contracta area (VCA) was obtained by 3D TTE by systematic and sequential cropping of the acquired 3D TTE data set. Assessments of aortic regurgitation (AR) by aortography and surgery are compared to measurements of VCA by 3D TTE and to 2D TTE measurements of vena contracta width (VCW). Aortographic or surgical grading correlated well with 2D TTE measurements of VCW (r = 0.92), but correlated better with 3D TTE measurements of VCA (r = 0.95), with improved dispersion between angiographic grades demonstrated by the 3D TTE technique. Live 3D TTE color Doppler measurements of VCA can be used for accurate assessment of AR and are comparable to assessment by aortography.

Quantification of Mitral Regurgitation by Live Three-Dimensional Transthoracic Echocardiographic Measurements of Vena Contracta Area: 3D TTE VENA CONTRACTA AREA FOR MR

We evaluated 44 consecutive patients who underwent standard two‐dimensional (2D) and live three‐dimensional (3D) transthoracic echocardiography (TTE), as well as left heart catheterization with left ventriculography. Mitral regurgitant vena contracta area (VCA) was obtained by 3D TTE by systematic and sequential cropping of the acquired 3D TTE data set. Assessment of mitral regurgitation (MR) by ventriculography was compared to measurements of VCA by 3D TTE and to 2D TTE measurements of MR jet area to left atrial area (RJA/LAA), RJA alone, vena contracta width (VCW), and calculated VCA. VCA from 3D TTE closely correlated with angiographic grading (rs= 0.88) with very little overlap. VCA of <0.2 cm2 correlated with mild MR, 0.2–0.4 cm2 with moderate MR, and >0.4 cm2 with severe MR by angiography. Ventriculographic grading also correlated well with 2D TTE measurements of RJA/LAA (rs= 0.79) and RJA alone (rs= 0.76) but with more overlap. Assessment of VCW and calculated VCA by 2D TTE agreed least with ventriculography (rs= 0.51 and rs= 0.55, respectively). Live 3D TTE color Doppler measurements of VCA can be used for quantitative assessment of MR and is comparable to assessment by ventriculography.

Hormone Replacement Therapy and Inflammation. Interactions in Cardiovascular Disease

Inflammation plays a central role in the pathogenesis of many forms of vascular disease, including atherosclerosis. Atherogenesis begins with endothelial damage, and the damaged endothelium expresses adhesion molecules, chemokines, and proinflammatory cytokines that direct atherosclerotic plaque formation and spill into the circulation as biomarkers of atherosclerotic disease risk. Menopausal hormone therapy, including a variety of estrogen preparations with or without a progestin, has negative modulatory effects on most of these soluble inflammatory markers, including E-selectin, vascular cell adhesion molecule-1, intercellular adhesion molecule-1, monocyte chemoattractant protein-1, and tumor necrosis factor-alpha, inconsistent effects on interleukin-6, and stimulatory effects on transforming growth factor-beta, a vasoprotective cytokine. In contrast, C-reactive protein, a circulating proinflammatory cytokine produced in both liver and atherosclerotic arteries, increases in response to oral conjugated estrogens but not to transdermal estrogen. Although C-reactive protein is clearly linked to increased cardiovascular disease risk in women, the hormone-induced rise in this biomarker is not associated with increased risk and may be related to a first-pass effect of C-reactive protein production in the liver after oral estrogen absorption. Many important questions about the effects of ovarian hormones on vascular inflammation and the pathogenesis of vascular disease cannot be answered in human subjects. Insights from fundamental mechanistic studies in animal models are needed to delineate the cellular/molecular events that determine whether these hormones protect or injure blood vessels.

Increased protein O-GlcNAc modification inhibits inflammatory and neointimal responses to acute endoluminal arterial injury

Inflammation plays a major role in vascular disease. We have shown that leukocyte infiltration and inflammatory mediator expression contribute to vascular remodeling after endoluminal injury. This study tested whether increasing protein O-linked-N-acetylglucosamine (O-GlcNAc) levels with glucosamine (GlcN) and O-(2-acetamido-2-deoxy-d-glucopyranosylidene) amino-N-phenylcarbamate (PUGNAc) inhibits acute inflammatory and neointimal responses to endoluminal arterial injury. Ovariectomized rats were treated with a single injection of GlcN (0.3 mg/g ip), PUGNAc (7 nmol/g ip) or vehicle (V) 2 h before balloon injury of the right carotid artery. O-GlcNAc-modified protein levels decreased markedly in injured arteries of V-treated rats at 30 min, 2 h, and 24 h after injury but returned to control (contralateral uninjured) levels after 14 days. Both GlcN and PUGNAc increased O-GlcNAc-modified protein levels in injured arteries compared with V controls at 30 min postinjury; the GlcN-mediated increase persisted at 24 h but was not evident at 14 days. Proinflammatory mediator expression increased markedly after injury and was reduced significantly (30-50%) by GlcN and PUGNAc. GlcN and PUGNAc also inhibited infiltration of neutrophils and monocytes in injured arteries. Chronic (14 days) treatment with GlcN reduced neointima formation in injured arteries by 50% compared with V controls. Acute GlcN and PUGNAc treatment increases O-GlcNAc-modified protein levels and inhibits acute inflammatory responses in balloon-injured rat carotid arteries; 14 day GlcN treatment inhibits neointima formation in these vessels. Augmenting O-GlcNAc modification of proteins in the vasculature may represent a novel anti-inflammatory and vasoprotective mechanism.

Gender and Blood Pressure

The prevalence, impact, and control of hypertension differ between the sexes in the US population. In addition, pregnancy, oral contraceptive use, and menopausal hormone therapy May influence blood pressure regulation in ways that have therapeutic implications for some women. Whether gender should be a significant consideration in the choice of individual antihypertensive drugs continues to be a topic of intense interest and debate. This brief review will discuss recent findings that bear on considerations of gender in the management of hypertension, particularly among older women.

Aging leads to increased levels of protein O-linked N-acetylglucosamine in heart, aorta, brain and skeletal muscle in Brown-Norway rats

Changes in the levels of O-linked N-acetyl-glucosamine (O-GlcNAc) on nucleocytoplasmic protein have been associated with a number of age-related diseases such as Alzheimer’s and diabetes; however, there is relatively little information regarding the impact of age on tissue O-GlcNAc levels. Therefore, the goal of this study was to determine whether senescence was associated with alterations in O-GlcNAc in heart, aorta, brain and skeletal muscle and if so whether there were also changes in the expression of enzymes critical in regulating O-GlcNAc levels, namely, O-GlcNAc transferase (OGT), O-GlcNAcase and glutamine:fructose-6-phosphate amidotransferase (GFAT). Tissues were harvested from 5- and 24-month old Brown-Norway rats; UDP-GlcNAc, a precursor of O-GlcNAc was assessed by HPLC, O-GlcNAc and OGT levels were assessed by immunoblot analysis and GFAT1/2, OGT, O-GlcNAcase mRNA levels were determined by RT-PCR. In the 24-month old animals serum insulin and triglyceride levels were significantly increased compared to the 5-month old group; however, glucose levels were unchanged. Protein O-GlcNAc levels were significantly increased with age (30–107%) in all tissues examined; however, paradoxically the expression of OGT, which catalyzes O-GlcNAc formation, was decreased by ∼30% in the heart, aorta and brain. In the heart increased O-GlcNAc was associated with increased UDP-GlcNAc levels and elevated GFAT mRNA while in other tissues we found no difference in UDP-GlcNAc or GFAT mRNA levels. These results demonstrate that senescence is associated with increased O-GlcNAc levels in multiple tissues and support the notion that dysregulation of pathways leading to O-GlcNAc formation may play an important role in the development of age-related diseases.

Aged rats lose vasoprotective and anti-inflammatory actions of estrogen in injured arteries.

Objective: 17&bgr;-Estradiol (E2) negatively modulates neointima formation, leukocyte infiltration, and proinflammatory mediator expression after vascular injury in young (10-wk-old) ovariectomized (OVX) rats. Trials of E2 in elderly postmenopausal women have not confirmed a vasoprotective effect. This study tested the hypothesis that responsiveness to E2 is lost in injured arteries of aged (12-mo-old) OVX rats. Design: E2- or vehicle-treated OVX rats underwent balloon injury of the carotid artery and were killed after 2 weeks for morphometric examination of arteries, after 24 hours for assessment of leukocyte infiltration, and after 2 hours for quantification of proinflammatory mediator mRNA expression. Results: Neointima formation was significantly reduced in aged compared with young vehicle-treated rats. E2 treatment had directionally opposite effects on intima/media ratios in aged (+75%) and young (−40%) rats. Injury induced increases in infiltrating total leukocytes, neutrophils, monocytes/macrophages, and expression of proinflammatory mediators in arteries of aged rats; E2 had no effect on these inflammatory responses to injury. Estrogen receptor &agr; and &bgr; protein expression were similar in carotid arteries of young and aged rats on immunofluorescence testing. Conclusions: Aged OVX rats lose the vasoprotective and anti-inflammatory responses to exogenous E2 seen in younger animals. These results may be relevant to the lack of vasoprotection observed in outcome trials of estrogen therapy in postmenopausal women.

Inhibition of transforming growth factor-β signaling induces left ventricular dilation and dysfunction in the pressure-overloaded heart

This study utilized a transgenic mouse model that expresses an inducible dominant-negative mutation of the transforming growth factor (TGF)-beta type II receptor (DnTGFbetaRII) to define the structural and functional responses of the left ventricle (LV) to pressure-overload stress in the absence of an intact TGF-beta signaling cascade. DnTGFbetaRII and nontransgenic (NTG) control mice (male, 8-10 wk) were randomized to receive Zn(2+) (25 mM ZnSO(4) in drinking H(2)O to induce DnTGFbetaRII gene expression) or control tap H(2)O and then further randomized to undergo transverse aortic constriction (TAC) or sham surgery. At 7 days post-TAC, interstitial nonmyocyte proliferation (Ki67 staining) was greatly reduced in LV of DnTGFbetaRII+Zn(2+) mice compared with the other TAC groups. At 28 and 120 days post-TAC, collagen deposition (picrosirius-red staining) in LV was attenuated in DnTGFbetaRII+Zn(2+) mice compared with the other TAC groups. LV end systolic diameter and end systolic and end diastolic volumes were markedly increased, while ejection fraction and fractional shortening were significantly decreased in TAC-DnTGFbetaRII+Zn(2+) mice compared with the other groups at 120 days post-TAC. These data indicate that interruption of TGF-beta signaling attenuates pressure-overload-induced interstitial nonmyocyte proliferation and collagen deposition and promotes LV dilation and dysfunction in the pressure-overloaded heart, thus creating a novel model of dilated cardiomyopathy.